The government's environmental advisers are prepared to approve the third runway at Chek Lap Kok after the airport operator offered new and additional plans to protect the marine ecology.
The plans will cover a period before and during construction and include efforts to protect the endangered Chinese white dolphin that may extend across the border, the advisers say.
One, Dr Hung Wing-tat, said they were inclined to endorse the runway's environmental impact report, with conditions.
"They have responded to our concerns and their plans will cover short, medium and long-term [action] in a comprehensive and positive manger," said Hung, vice-chairman of the Advisory Council on the Environment's impact assessment subcommittee. "But we are not completely satisfied as the concrete details of how to implement the plan have to be worked out," he said.
The report had been a major stumbling block for the project, with council members just two weeks ago berating the Airport Authority for not coming up with anything new to protect dolphins while 650 hectares of sea are being reclaimed.
Under proposals disclosed yesterday, the authority will provide up to HK$300 million to finance conservation and research on marine ecology and fisheries resources, possibly extending across the border although details of this were not given. A management plan for high-speed ferry traffic will be enacted while a dedicated team will monitor marine traffic near the site.
Hung said conditions for approving the report had yet to be drafted and the authority would be asked for more information by the council, which will make a decision on September 15.
On Monday, the Agriculture, Fisheries and Conservation Department suddenly reported that it was ready to introduce bills to designate two marine parks proposed 14 years ago - seen by conservationists as a move to take pressure off the authority.
But the department told the subcommittee that the move had nothing to do with the runway.
Subcommittee member Dr Billy Hau Chi-hang said he still had reservations about the report despite new measures he regarded as just "conceptual plans".
Dr Samuel Hung Ka-yiu, chairman of the Dolphin Conservation Society, said the decision process was not transparent.
Other questions remain over the runway - not least how it will be funded.