Melbourne drivers are being promised shorter commute times on the Monash Freeway, with the state and federal governments promising an additional $367.5 million for more lanes.

The funding boost takes the total cost of the freeway expansion to $1.4 billion, with construction expected to begin by 2020 and be ready for drivers by late 2022.

Mr Morrison and Victorian premier Dan Andrews are set to announce the extra funding in outer Melbourne on Wednesday.

Mr Andrews says the upgrade will improve the freeway’s safety and reduce congestion for the 470,000 drivers who use it each day.

“We’ve already delivered the first stage of upgrades on the Monash and we’re getting on with the next – to get people in Melbourne’s booming south east home safer and sooner,” he said.

RACV senior manager of transport Peter Kartsidimas said drivers who get stuck in traffic jams would welcome the decision, which would get them home to their families sooner.

“This project is a top order congestion-busting priority for Melbourne and we’re going to get it done,” Prime Minister Scott Morrison said.

“It’s one of many projects that are needed across the state to ease the congestion problem. It is not the only one, but we are pleased the government is focusing on transport improvements,” he told 3AW.

However, he said he also wanted the governments to commit to a third rail tunnel through the city to get more people off roads altogether.

Eight to 10 lanes will be added to the Monash freeway between Springvale Road and Eastlink, while the Clyde Road and Cardinia Road section will be expanded with four to six lanes.

The upgrade also includes two extra lanes for O’Shea Road in each direction, a new outbound entry at Police Road and modifications to the outbound Jacksons Road entry to Eastlink.

Federal Urban Infrastructure Minister Alan Tudge says the project will cut nine minutes from a morning peak hour commute between Pakenham and Malvern, and 13 minutes from an evening trip at peak hour.