This also explains why development in rural areas can either proceed incredibly quickly or extremely slowly, depending on how much risk people are willing to take.

If rules are followed, a long and complex procedure is set in motion. The developer begins by asking if the site is privately owned, if it is subject to any land use zoning control and whether the development plan is in line with that.

If the development is at odds with the zoning, planning permission or even rezoning approval - for instance, changing the land use from green belt to village development - approval must be sought from the Town Planning Board. Otherwise, the developer can seek approval directly from the Lands Department and Buildings Department.

Planning permission usually takes two months. The public is given three weeks to comment before the board makes a decision. A rezoning request takes at least nine months.

As well as the time it takes, growing public awareness of the environment and planning issues in the New Territories is helping spur an upsurge in illegal development, planners say.

'Public views have become more critical when it comes to giving planning permission, and that increases the risks and uncertainties faced by land owners,' Ng Cho-nam, a professor at the University of Hong Kong and former Town Planning Board member, said.

'Even if they are patient enough to go through all the required steps, they won't be guaranteed permission from the board,' Ng said. 'That's why many of them would rather develop first and apply for permission later.'

To complicate matters further, planning applications are sometimes made by one party in respect of sites owned by others, including the government, with applicants either proposing to build on or even rezone the land. But the actual construction still hinges on the ownership and subsequent approvals from other departments such as lands and buildings.

It is not uncommon in the New Territories for owners or developers to take the risk and just go ahead with a project. One example is a pond in Luk Keng, which is part of a wetland habitat that supports a large diversity of dragonflies. Construction waste was dumped in the pond, but the owners only sought retrospective approval after planning officers threatened enforcement action.

The board rejected the application and the owners were compelled to remove the waste, but the ecology of the pond may never recover.

Landowners in Ho Sheung Heung, Sheung Shui, took the same approach, seeking approval to build a small house only after dumping construction waste nearby. The application was approved, with the board taking into account only the merits of the land use, not the dumping.

While the city's planning system is considered an open one that allows a degree of public participation, a loophole exists when it comes to policing some areas of the New Territories. The Planning Department can only enforce unauthorised development rules - such as for illegal dumping and building works - in areas under the Development Permission Area Plan. But it cannot police areas under the Outline Zoning Plan. The DPA plan was introduced in an amendment to the Town Planning Ordinance in 1991. It was designed to regulate the booming cargo container and wreckers' yards in the New Territories in the 1980s.

These DPAs are to be changed to Outline Zoning Plan within three years, but the enforcement power for the latter will apply.

This restriction on policing explains why some dumping that has been going on for years has not been resolved. For example, in a case of massive soil dumping at Tung Tsz in Tai Po - even though the site is in a green belt zone, it is classified as Outline Zoning Plan.

It also explains why the Planning Department generally has no enforcement power in new towns like Tsuen Wan, Kwai Chung and some parts of Sha Tin, where outline zoning plans were introduced and no DPAs were ever in force.

But the absence of a zoning plan in some parts of the New Territories does not necessarily mean the government is powerless to regulate developments or that developers can build wherever they like. Officers can still make use of land lease controls.

The best illustration of this was the government's takeover of a private site in Tei Tong Tsai on Lantau Island, where an underground columbarium was being developed on a site without any land-use zoning.

Any attempt to convert a site for uses not in line with the land lease requires prior approval and lease modifications from the Lands Department, which may incur a land premium. Since it is a contract between the government and tenant, land lease terms may be interpreted differently, and this can lead to legal disputes.

Apart from the planning system and land lease control, developments in the New Territories are also regulated by the Environmental Protection Department if they are designated as having an adverse impact under the Environmental Impact Assessment Ordinance.

But most developments in the New Territories - including small houses and columbariums - do not require environmental impact assessments.

In the case of a private site that is part of a country park, land owners wanting to build a house must get approval from the Agriculture, Fisheries and Conservation Department and the Lands Department. But the departments cannot stop them if they excavate sites and remove trees, as the Country Parks Ordinance does not cover private sites in country parks.

That is why the departments did not prosecute the de-facto land owner who removed trees and wanted to build two public parks with accommodation for the elderly inside Plover Cove Country Park.

The de-facto owner, who had rented the private site from indigenous villagers for 50 years, was fined just HK$2,500 and HK$1,000 in April for felling 13 small trees and driving vehicles into the park.

The only way to tackle the problem - in particular preventing sites not subject to planning controls from being destroyed by illegal developments - is to work with land owners to get the most out of the sites, according to Ng. He suggested that this could be done by allowing businesses on such sites that are compatible with the environment.

For example, villages could offer short-term accommodation such as hostels for visitors on eco tours. 'In that case, villagers might consider starting up a business instead of selling their land to developers,' Ng said.

But he said application procedures for running hostels were too costly and complicated, which deterred villagers from refurbishing their old dwellings.