Labor has promised to spend $180 million over four years towards duplicating key sections of Heathcote Road if elected to government on March 25.
Shadow Minister for Roads John Graham said the funding would be additional to what was allocated for the ongoing duplication of the Woronora River bridge and approaches.
Mr Graham said extra overtaking lanes and safety enhancements would be provided with the new funding.
Options would also be explored to provide two lanes in each direction over the Woronora Bridge and on its approaches, he said.
Mr Graham made the promise with Labor candidate for Heathcote Maryanne Stuart and MLC Mark Buttigieg.
"The current government has botched the Heathcote Bridge widening and duplication project," he said.
"After years of promises and tens of millions spent, motorists still have a single lane in either direction.
"Only a Minns Labor government will get this crucial project moving.
"Local roads like Heathcote Rd have been neglected for 12 years by a government obsessed with Sydney toll roads."
"The region is booming but government neglect of essential infrastructure is holding it back."
Ms Stuart said sitting MP Lee Evans and Liberal government had promised to upgrade Heathcote Road since 2011.