New signs warning motorists about koalas on Heathcote Road have been welcomed, but concerns have been raised about the time being taken by transport officials to introduce mitigation measures at key crossings.

The NSW Koala Strategy team has recorded 10 koala deaths on Heathcote Road since October 2022, eight of which have been in the Deadmans Creek area.

One recent casualty, the 4-month-old koala joey Millie, who was hit on the road with her mother in July, recently died while in care.

Heathcote MP Maryanne Stuart announced on September 7 Transport for NSW was placing six permanent and two temporary signs between Princes Highway and Deadmans Creek.

Ms Stuart said the new signs would complement other action taken on Heathcote Road:

• Stage 1, which has been completed, involves an upgrading of koala access under Deadmans Creek Bridge via a platform on the western side and a concrete walkway on the eastern side.

• Stage 2 involves fencing either side of Heathcote Road to the north and south of Deadmans Creek bridge to prevent animals from entering the road corridor and direct them to the bridge underpass and two nearby culverts under Heathcote Road.

Ms Stuart said Transport for NSW had advised it would continue investigations on ways to further ensure the safety of koalas with $1.5 million in funding that has been provided by the NSW Koala Strategy to begin the planning of the next stage of improvements at Deadmans Creek.

This involves the potential of koala exclusion fencing, dependent on an environmental impact statement (EIS) and review of environmental factors (REF).

Sutherland Shire Environment Centre welcomed the new signs and Ms Stuart's "ongoing commitment to protecting koalas across the Heathcote electorate".

"Heathcote road has become a notorious koala kill hot spot, near the ANSTO precinct and the newly upgraded Woronora Bridge, and also along the stretch of road between Pleasure Point and Sandy Point around Deadmans Creek," the centre said in a statement.

"Serious concerns remain about the speed with which Transport NSW is putting in place koala road kill mitigation works at the Sandy Point - Deadmans Creek section of Heathcote Road. This section of the road is in the Holsworthy electorate.

"In December 2021, Transport for NSW released a report with recommendations to prevent koala road kill at Deadmans Creek, but most of the measures have not yet been acted on."

Dr Catherine Reynolds, of the Sutherland Shire Environment Centre, said, "That the deaths keep happening is a troubling indication that the minimal work Transport NSW has carried out has not offered a solution."

John Souvleris, another member of the environment centre, said, at an onsite meeting at Deadmans Creek on August 2, Transport for NSW had advised the work schedule for stage 2 had been delayed and would not commence until in 2024, or possibly 2025.

"They said the timing will depend on an EIS (Environment Impact Statement) report required for the wetlands and a DA which would need to be lodged with Liverpool Council," he said.

Mr Souvleris said mitigation work at the Woronora Bridge upgrade was happening, but at a very slow pace.