The $1bn in savings found through a review of the $34.5bn Suburban Rail Loop has already been rediverted, with Ben Carroll pumping the cash into must-win electorates ahead of the election.

The Premier will on Friday pledge $494m for a major upgrade to Somerton Rd, bringing the total to more than $1.2bn in spending on road upgrade commitments made in just three days.

He has now promised major road upgrades in Greenvale, Meadow Heights, Roxburgh Park and Epping in the north, and Seabrook and Wyndham Vale in Melbourne’s west.

Labor sources said it was hoped the big spending would be welcomed by locals, and MPs, in fast-growing outer suburbs who felt neglected at the expense of the divisive SRL project.

But it was also critical to fend off advances by One Nation who were looking to capitalise on growing anti-government sentiment in Melbourne’s northern and western suburbs.

Pollster Kos Samaras said latest polling showed Coalition was poised to win a swag of three-way contests across the state.

He said they could be particularly effective in the north and west.

One Labor source said Mr Carroll was “finally rediverting SRL money to where it always should have been spent, in local heartland communities.”

The Somerton Rd upgrade will widen 4km of the critical east-west corridor from two lanes to six as between Fleetwood Drive and Roxburgh Park Drive.

Three key intersections at Aitken Boulevard, Magnolia Boulevard and Roxburgh Park Drive would also be upgraded while a new walking and cycling path would be built.

Final planning and procurement for the project is expected to begin 2027, with construction to start in the following term of government.

the government said the project was affordable because of a series of savings including $1bn in SRL savings.

While $1bn in savings has already been identified, Labor was expecting to find a further billion dollars in savings through technical and engineering reviews of the project.

As part of the savings, the 26km SRL East between Cheltenham and Box Hill will be scaled back by dumping underground station interchanges at Box Hill and Glen Waverley.

The costs of building carparking in Glen Waverley will also be reduced, while a second station entrance at Clayton will be cut, along with “complex pedestrian bridges” in Burwood and Cheltenham.

“We have listened to the community. Better local roads in growing areas are my priority,” Mr Carroll said.

“Melbourne’s north is growing — this upgrade will save local families precious time.”

It comes after Mr Carroll promised a $448m upgrade blitz across three critical roads in Melbourne’s west on Thursday, and $270m in northern suburbs upgrades on Tuesday.

Those announcements included $195m for the widening of Point Cook Road in Seabrook, $170m to widen Taylors Road, and $83m to double the capacity of the intersection between Ballan Road and Bolton Road in Wyndham Vale.

Mr Carroll also promised residents in Epping that $270m would be spent upgrading Findon Rd to make the ageing choke-point safer for residents in the outer north.

“Roads, roads, and more roads are such an important part of what I will do as premier … fixing potholes, and getting people home faster,” he said.