CONSERVATIONISTS are sounding the alarm amid claims one of Australia's richest men is putting his development before the health of an endangered Tweed koala population near Kingscliff.

Bob Ell, who has an estimated wealth of $1.26 billion, is pushing through his company Leda Holdings to change koala protection clauses at his Kings Forest estate.

The 4500-house residential development due to be built between Kingscliff and Cabarita will replace what is mostly rural or farming land on a corridor between Tweed Coast Rd and the M1.

Jenny Hayes, Team Koala Tweed president, said the group's 863 members were "really gutted” after learning of the changes Leda wanted to make.

"It's a very stressful time,” Ms Hayes said. "All of this work our amazing group has done over eight years has just gone up in smoke unless we act now.”

Ms Hayes said koala protection measures already attached to the development were the minimum needed for the endangered population to survive.

She said the developer wanted to reduce reserve corridors from 100m to 50m and reduce the number of primary koala food trees.

"They don't want to plant any primary koala food trees whatsoever,” she said. "And they don't want to plant them in cleared areas.

"What offsets are about is planting primary food trees in cleared areas so the koalas can re-establish themselves.”

Ms Hayes said Leda also wanted to remove the need to install koala calming devices near roads and reduce the number of wildlife underpasses from five to one.

A Leda spokesman said the community had an opportunity to have its say on proposed changes and encouraged submissions to be made to the NSW Department of Planning and Environment.

"We're very mindful of the trust the community puts in us,” he said.

He said Leda was simply following the same process as any developer seeking to make modifications through the NSW Department of Planning and Environment and the department would consider the proposal against community input.