The office will be tasked with planning, assessing, designing and implementing various development and conservation initiatives, according to the plan.

However, green groups were disappointed to find there would be just one conservation post in the office, compared with more than 15 engineers, town planners and architects.

“The input does not match the government’s promise,” said Dr Cheng Luk-ki, head of scientific research and conservation with Green Power.

“We doubt whether the government really puts conservation in first place, as it says.”

Cheng said the office should have at least three divisions overseeing conservation planning, implementation and law enforcement.

Instead of reporting to the Development Bureau, the teams should come under the Environment Bureau while cooperating with advocacy groups, he added.

Cheng said advocacy groups were lobbying lawmakers to veto the office proposal unless the government redesigned the office’s manpower structure.

The Development Bureau rejected the criticism. It said there would be three forestry officers with relevant experience in nature conservation.

“It must be stressed that successful implementation of conservation initiatives is normally a joint effort of professionals from different disciplines,” a spokeswoman said.

“All professional staff of the Sustainable Lantau Office will be fully aware of the importance of conservation initiatives on Lantau,” she said.

The green groups also criticised the absence of concrete measures in the Lantau blueprint to protect the island’s ecosystem.

In a joint letter, 11 groups urged the government to set up more reserves, expand marine parks and limit the influx of trucks and tourists.

Such efforts would be essential to protect vulnerable species including buffaloes, dolphins and butterflies, the groups said.

The number of Chinese white dolphins in four areas off Lantau dropped from 188 in 2003 to 65 in 2015, according to the Hong Kong Dolphin Conservation Society.

Yuki Lui Hiu-ying, the group’s project officer, said dolphins living on the north side of the island were forced to move due to construction work.

If a larger sea area off the southern and western parts of Lantau could be designated as marine parks, dolphins there would be protected from disturbance caused by high-speed vessels, she said.

The Development Bureau said the government was carefully examining the feasibility of various proposals.

Conservationists say the island has already suffered irreversible damage from unauthorised construction, with the development plan boosting land prices on Lantau.

Cheng said Mui Wo, Pui O and Tong Fuk were among the areas that had seen severe environmental destruction.

“In the plan, the government talks about how beautiful and resourceful Lantau is,” Cheng said. “But if the authorities do not change their mindset, the resources will soon be gone.”