The government on Wednesday vowed to avoid affecting the habitats and flight corridors of migratory birds "as much as possible" when creating the planned San Tin Technopole project.

Nine environmental groups on Tuesday called on the administration to make changes to the 627-hectare development, warning it will encroach on 248 hectares of wetland conservation area.

The Hong Kong Bird Watching Society said the land is ecologically rich with over 100 species, including critically endangered birds.

Responding to media enquiries, the Development Bureau said it has reserved a 300-metre wide strip near the wetland to preserve an existing flight corridor for migratory birds.

A bureau spokesperson also said around two-thirds of the area is of low ecological value.

"In fact, 159 hectares of the 248 hectares are already brownfields, filled fish ponds, and other lands with lower ecological value," the spokesperson said.

"Of the remaining 90 hectares of fish ponds proposed to be filled, half of them have not been used to fish culturing or have been abandoned for many years."