A Planning Department source said the damaged area is ecologically sensitive because it is close to a water catchment area and extensive earthworks had left piles of soil on government land. The source added that the destruction was just the tip of the iceberg in Sai Kung. Natural areas near Ho Chung and Sheung Yeung, for example, were also threatened by village development.

Trees on a slope near Tai Mong Tsai village were cut down to clear a path for moving the construction equipment and vehicles.

The Agriculture, Fisheries and Conservation Department is investigating the unauthorised felling. A department spokesman said rare plants such as incense trees were in the area.

Hong Kong Institute of Planners vice-president Chan Kim-on said planning conditions should be imposed by the government when it approved construction of new houses to avoid damage being caused to the environment.

For example, an infrastructure plan for a village development should be submitted and approved by the government as a condition to the application, Mr Chan said.

'A village house should be approved only when it is proved accessible,' he said. 'Even if a new road is necessary, it has to be built legally and in an environmentally friendly way.'

Ultimately, he said, the right to build a three-storey house granted to indigenous male villagers should be scrapped to minimise development pressure on rural areas.

Latest government figures show that of the 1,394 applications for small-house construction permits received from January to November last year, about 14 per cent were for Sai Kung projects.

A spokesman for the Lands Department confirmed last week that six of the 12 new village houses planned for the Tai Mong Tsai development had already been approved by the department. He said officers had been sent to the site on December 17 after the department received a complaint.

During the inspection, a muddy track surrounded by evidence of tree-felling was found, possibly involving government land. A metal framework was also found to have been erected on government land, 'possibly for the construction of a bridge', he said, adding that that construction had been removed after a government warning was posted at the site.

But he said there was no tree-preservation clause attached to conditions relating to the private development, and so tree preservation would have been impossible.

The Small House Policy was introduced in 1972 with the objective of improving the prevailing low standard of housing in rural areas. Under the policy, male indigenous villagers aged 18 or above can apply to build a small house once in their lifetime.

No environmental-impact assessment is required by the Lands Department, which is responsible for approving the applications.