The Victorian premier, Ben Carroll, has made an about-face, committing to pushing ahead with the first stage of the Suburban Rail Loop while promising to reduce its total cost by about 6%.

Carroll will on Tuesday announce changes to the scope of the first stage of the project, known as SRL East – a 26km stretch of tunnels between Cheltenham and Box Hill – estimated to save $1bn.

He will also order an “independent, technical review” to identify a further $1bn in savings.

No further contracts will be awarded until the review is complete but the government has stressed all current works will continue, with tunnelling between Burwood and Glen Waverley set to begin soon.

Carroll said the changes showed he “respects” taxpayer money.

“The SRL will be built on time. Today’s changes mean it will be built under budget,” he said.

Combined, the two measures would reduce the total cost of SRL East by 6% to about $32.3bn from a maximum $34.5bn contained in the project’s 2021 business and investment case.

Carroll will also annouce that the Suburban Rail Loop Authority, the statutory agency responsible for planning and delivering the project, will be folded into the Victorian Infrastructure Delivery Authority. The move was already under way prior to Carroll becoming premier four weeks ago.

Since Carroll took on the Labor leadership, he has sought to differentiate himself from his predecessors, Jacinta Allan, and Daniel Andrews, who both championed the orbital train line.

In his first week as premier, Carroll said he would not tear up the project’s contracts. But he wouldn’t rule out redirecting billions of dollars earmarked for the SRL to other projects, such as Melbourne Airport rail.

Then, in radio appearances on Monday, he suggested projects other than SRL were more important to Victorians.

“The Suburban Rail Loop, an orbital line, makes sense, but it cannot be crowding out everything else we need to do as a government. Airport Rail, Melton electrification, filling potholes and doing the job properly – these are the things Victorians want from their leader and their government,” Carroll told 3AW.

On ABC Radio Melbourne, he said work on SRL would go ahead but there were “other projects that are so much more needed and urgent”.

“There is a contract in place and that work will go ahead. But I am also having a very good look at how we fix up potholes, get on with Airport Rail, get on with Melton electrification,” Carroll said.

The changes to SRL East’s scope includes scrapping underground station interchanges at Box Hill and Glen Waverley, a second station entrance at Clayton and “complex” pedestrian bridges in Burwood and Cheltenham. A multilevel car park at Glen Waverley, which was meant to replace about 400 spots lost due to construction of the new station, will be scrapped.

The SRL Community Projects Fund, designed to support local community groups with grants of between $10,000 and $80,000 while construction is under way, will also end at the completion of the current round.

The government also said some future precinct works – to transform the areas around the new stations into housing hubs – will be scaled back.

It has allocated $11.8bn to SRL East while the federal government has handed over $6bn, including $3.8bn in May’s federal budget. About $14.5bn worth of contracts have been signed.

The state opposition leader, Jess Wilson, has said if the Coalition is elected in November, she will pause and review the project.