The start of work on a $73 million project to widen the narrow bridge on Heathcote Road at Engadine has been pushed back to the first half of 2022.
"We are currently finalising detailed design for the bridge improvements," Transport for NSW said in an October update.
"Construction work is expected to start in the first half of 2022, and we will keep the community updated on the progress of the project."
The project will see the one lane in each direction retained but widened to standard lane widths of three and a half metres with 1.2 metre shoulders.
The state government rejected appeals by Sutherland Shire, Wollongong and Liverpool councils to duplicate the bridge.
Work was scheduled to start by the end of 2021, with Heathcote Road between Engadine and Lucas Heights closed for up to six months.
Transport for NSW said in April 2021 the project would be carried out in conjunction with the upgrade of Linden Street, Sutherland, by the one contractor and work would start at the end of this year.
"This will allow any interrelated impacts from these projects, such as road and lane closures and detours, to be managed concurrently," a spokesman said at the time.