The NSW government will award a contract valued at around $2.2 billion for a project aimed at slashing travel time between Parramatta and the airport.
Premier Gladys Berejiklian and Transport Minister Andrew Constance announced expressions of interest for the upcoming toll-free Sydney Gateway project were open on Sunday.
"This project is critical to reducing travel times to and from the airport," Ms Berejiklian told reporters in Sydney.
The government estimates 10,000 heavy vehicles will be taken off Mascot's local streets as a result of the project.
Mr Constance said the effects of Gateway would be a "game changer" for everyone in the city.
"If you are travelling from the Blue Mountains to the domestic terminal you will not see a single traffic light," he said.
Mr Constance said the government estimated the contracts final price would be between $2.2 and $2.6 billion, with Gateway scheduled to open by 2023.