A spokesman took pains, however, to say: 'No building is found to be in immediate danger so far.'

Despite the high number of ageing buildings with clear defects, remedies are still in the talking stage. The URA is planning a forum in April to figure out urban-renewal strategies. Lawmakers are debating a basket of new measures, including a law that would compel owners of older structures to get regular professional building inspections.

The new survey of dilapidated buildings follows up an earlier one, done by the URA shortly after the tenement collapse of a year ago. That investigation found that about 2,000 buildings in Hong Kong were a 'potential danger'. The phrase was not defined.

'We will not release the full results of the report,' a top URA official said late last year. 'Releasing such information would have a serious impact on the value of the properties concerned and this would not be fair to the owners.

'There is no public safety concern since any building found with immediate danger will be fixed,' the official added. 'We are talking about blocks with potential danger and we will tell these owners and help them repair their homes.'

The To Kwa Wan tragedy prompted the Buildings Department to make its own survey last February. The department found that over half of Hong Kong's 4,000 buildings more than 50 years old were found to have obvious and minor defects. Most of the buildings were found in Kowloon City, Yau Tsim Mong and Sham Shui Po districts. Two needed emergency remedial work and got it.

Professor Law Chi-kwong, who specialises in urban renewal issues at the University of Hong Kong, called for more disclosure. He questioned the premise that flat prices would fall if the authority disclosed more details of its survey.

'The price could rise as the potential redevelopment value could be attractive to buyers,' he said. 'They can realise a much higher profit from redevelopment than owning a renovated flat,' he said.

Making public such information, without naming the buildings, would bolster public and owners' awareness of building maintenance, Law said.

A spokeswoman for the development agency yesterday declined to say if it would release details of the survey results.

Earlier this month, the Buildings Department brought charges against a contractor responsible for renovation work in a ground-floor shop done before the building at 45 Ma Tau Wai Road collapsed.

The contractor, who was not identified, was charged under a section of the Buildings Ordinance regarding work that causes injury or damage to property. The maximum penalty is HK$1 million and three years' jail. A Buildings Department spokeswoman said the Department of Justice decided to prosecute after studying forensic results and witness statements. Investigators found that renovation work had damaged structurally important columns, and two others.

Questions have been asked about whether Chak Oi-luen, owner of the collapsed building, will face any charges. Police have been investigating the case but have arrested no one so far.

Democratic Party lawmaker and solicitor James To Kun-sun said if prosecutors could prove the owner had instructed the contractor to remove the structural columns, knowing that could cause danger, she could be charged with inciting someone to violate the building law.

'But it looks unlikely the owner will be prosecuted,' To said.

In the Legislative Council, lawmakers are debating bills submitted by the Development Bureau meant to step up building safety.

A major step would be a new law requiring owners to conduct building inspections. Owners of buildings older than 30 years would have to hire a professional to examine the common areas of the blocks every 10 years. Those who failed to comply would face a fine of HK$50,000 and a year in jail.

The bill, finally tabled after nearly two decades of political haggling, is expected to take effect no sooner than year's end.

Other measures would equip building officials with court warrants to let them enter flats for inspections, and require owners to apply to the Buildings Department when subdividing flats to ensure they hire qualified contractors.

Property owners refusing to share costs of repairing common areas would be charged a 20 per cent surcharge of the expense. A unified scheme of building maintenance subsidies, run by the Housing Society and Urban Renewal Authority, would offer help to owners with financial difficulties.

These new measures require the amendment of dozens of regulations. Whether they will take effect soon will depend on how fast the bureau can secure lawmakers' approval.

Law said mandatory inspections would alleviate problems relating to older buildings, but the bill failed to answer some questions. Should government offer help to elderly people who cannot afford inspections? Should buildings more than 50 years old be exempted from mandatory inspection because they could be redeveloped soon anyway?

In the long run, he said, the hazards of old buildings would not be solved without addressing poverty in the city.

'The root of the problem is that we have a large number of poor families which create a continuous demand for dilapidated flats and subdivided flats,' he said, 'In other modern cities, these poor-condition flats are often demolished as they have no market.'

Redevelopment in the collapsed building's neighbourhood has not gone smoothly. The project, undertaken by the authority alone, was scheduled to commence acquisition last May. But it is still in a deadlock, eight months later.

Earlier this month, eight residents filed an appeal against the redevelopment, saying their flats, located on the street adjacent to the collapsed building, were excluded from the redevelopment boundary. The appeal - a first for the authority - will postpone the project by two months; acquisitions cannot commence until it is settled.

Chan Ming-chuen, one of the eight residents, said the authority's arrival had ruined a deal to sell his flat to an estate agency, which had been acquiring old buildings in the area before the collapse. Chan, in his 60s, urged the authority to include him in the project because his site had now become too small to be lucrative for private developers.

Although the authority is allowing tenants and owners to receive compensation before it takes their property, only two of the 159 property interests have been sold to the authority, and about half of the affected tenants have moved out.

The authority's HK$2 billion project will convert 33 blocks on Ma Tau Wai Road and Chun Tin Street into two 30-storey blocks. Each will have 500 square metres of open space at ground level, 1,000 square metres of community facilities and street-level shops. The project is expected to create experimental 'no-frills' small to medium-sized apartments.

Unanswered questions

Was the building contractor licensed to carry out the work on the block?

If the contractor was not licensed, why is the building owner not liable for appointing it?

What are the conclusions of the police investigation?

Will the police prosecute the owner, and if so, with what charges?

How many of the buildings surveyed by the Urban Renewal Authority are structurally poor and in need of redevelopment?

Where are they?

In a fix

Statutory orders issued on buildings and the compliance rate

Orders for repairs/Number of repairs carried out

2008: 459/450

2009: 530/354

2010 (Jan-Nov): 1,268/232

Orders for removal of unauthorised work/Number removed

2008: 32,847/26,026

2009: 31,453/23,499

2010 (Jan-Nov): 19,317/13,608

Note: repairs carried out and removals may not be in response to orders issued in the same year

Source: Buildings Department

New measures

Mandatory building and window inspections.

Legal amendment to enable building inspectors to apply for court orders to enter flats.

Regulations on subdivided flats.

Surcharge for property owners who refuse to share costs of repairing common areas.

Stronger enforcement of rules on illegal structures.

Unified Housing Society and Urban Renewal Authority scheme for building maintenance subsidies.

Possible legislation to tackle water seepages.

Control scheme and regular safety checks for signboards.

Developments since tragedy

January 29, 2010

The 53-year-old tenement, block J in 45 Ma Tau Wai Road, collapses, killing four and leaving dozens homeless

February 2010

Emergency inspection of buildings more than 50 years old completed in one month; Buildings Department knocks down blocks G and H structurally linked to the collapsed block

February 24, 2010

Urban Renewal Authority announces redevelopment project covering Ma Tau Wai Road and half of Chun Tin Street behind

April 2010

Government investigators conclude that 'external force' caused three structural columns to fail in block J. They later say ground floor renovation work played a role

October 2010

Measures announced to improve building safety

December 2010

Development Bureau approves redevelopment plan for collapse site

January 18, 2011

Eight families from Chun Tin Street, excluded from the redevelopment plan, file appeal with the Urban Renewal Authority

January 20, 2011

Building contractor, responsible for the renovations on block J, to be prosecuted. Case will be heard on February 16

Source: Buildings Department