She also questioned whether the long-standing 'exempted houses' policy, which allows indigenous villagers to build three-storey houses on their land, was still valid in view of the development of the New Territories.

Unauthorised structures, ranging from rooftop buildings and canopies to additional storeys and even entire buildings, are thriving, with more than 6,500 cases detected by the District Land Office last year. Actual numbers, Ms Tai said, are likely to be higher.

Between February 2000 and December last year, the Lands Department referred 571 cases to the Buildings Department, of which 200 were passed back to the Lands Department. The Buildings Department served 108 removal orders, of which only 21 were complied with.

The ombudsman's office recommended a two-pronged policy that would simply impose penalties in non-serious cases while rigorously enforcing more serious cases, such as those that posed safety hazards.

'Because of a shortage of resources and lack of priority being given to tackling unauthorised building works, they are allowed to ...get out of hand and the message is very clear that government departments do not mean business and are mere paper tigers who take no action,' Ms Tai said.

'Perhaps there is a way to concentrate efforts on the more serious encroachments, come up with a common yardstick and consistent policy on the problem. Don't just go through the motions.'

Ms Tai said the issue sometimes became politicised, with villagers complaining that officers are infringing on their rights as indigenous inhabitants.

Lands Department Director Patrick Lau Lai-chiu admitted that there had been problems of co-ordination between the Lands and Buildings departments.

'I would not deny that, at the initial stage of co-operation concerning division of labour, there might be some co-ordination problems of understanding and enforcement,' he said in a joint press conference with acting Director of Buildings Cheung Hau-wai.

'But recently, we have improved the co-operation [which] has been upgraded to assistant director level.'

Mr Cheung said they had improved division of labour since September last year so that buildings officers could still issue removal orders if they found evidence of illegal construction activities, even after works had been completed.

Mr Lau pledged a joint review of procedures to curb unauthorised building work on small houses.

But he said the issue had social, legal and resource ramifications, which required time and public consultation to sort out. There were also budget constraints, he said.

'At present there are only 50 frontline lands officers to enforce land leases and oversee lease-related issues in the New Territories.