Victoria’s premier has defended her government’s costing of the first stage of the state’s mammoth Suburban Rail Loop (SRL) project in the face of scrutiny from the federal government and Australia’s peak infrastructure body.

Jacinta Allan said on Sunday she was expecting the first stage of the project to remain within the existing budget.

“We’ve said Suburban Rail Loop East is a $30-34.5 billion project. We’ve awarded three projects and they’ve all been within the cost estimate,” she said.

She also addressed concerns raised by some residents near construction works about symptoms associated with the use of heavy machinery, saying “a lot of work” had been done with those affected.

The first stage of the 90 kilometre orbital rail tunnel designed to accommodate a growing Melbourne, known as SRL East, is underway and will connect the suburbs of Box Hill and Cheltenham. The first leg alone has been costed at up to $34.5 billion.

Amid growing criticism of the costly project, the federal government has asked its Victorian counterpart for answers after a report from Infrastructure Australia questioned the viability of the first stage of the SRL.

The report warned the project was expected to exceed its budget, posing a “major risk” to its viability, and said the business case underpinning it lacked detail.

On Saturday, Federal Housing Minister Clare O’Neil said her government was taking Infrastructure Australia’s critical evaluation of the initial phase of the project “really seriously”.

Victoria’s opposition has pledged to scrap the project.

Shadow Minister for Major Projects Evan Mulholland said it was concerning that the federal government was yet to commit to funding beyond an initial investment of $2.2 billion for the project.

“Almost the entire project is going to be banked on state government debt,” he said.

“It’s not good enough.”

Mr Mulholland also described the reports from residents feeling unwell due to construction work as “very concerning”.

Premier defends bundling project stages

Among the concerns raised by Infrastructure Australia was that the cost-benefit analysis of the first stage of the SRL relied on future stages to justify its benefits.

The premier defended the approach.

“Because it is a project that is being delivered in stages, you have to look at the benefits together,” Ms Allan said.

She said her government would continue to work with both the federal government and the infrastructure body.

“Victoria is a big and busy state and we need to invest in the transport infrastructure projects that support more homes, better access to schools, to universities, to hospitals,” she said.

“That’s why Infrastructure Australia has identified the Suburban Rail Loop on its priority list.

“That’s why if you look at the report, it goes to supporting to project, because it addresses those challenges that we just have to get on and address.”

Machinery change after residents feeling ‘woozy’

Michelle Hornstein lives in Heatherton, the suburb where a train stabling facility will be built as part of the SRL project.

She said she first started noticing symptoms she likened to motion sickness in mid-February while sitting at her desk working from home.

She said she felt “a little bit woozy” and the symptoms grew strong enough to prevent her from being able to carry on with her work.

“I could hear a bit of a hum outside, which was a new sound,” Ms Hornstein said.

“So I stepped outside into the backyard, and the hum was louder and the motion sickness straight away felt stronger.

“I straight away felt more nauseous.”

The secretary of the Kingston Residents Association said she was among a group of about 20 people who had reported the health issues associated with nearby works on the SRL.

Vibration rollers that were being used for ground compaction works have since been taken offsite and were no longer in use, according to the Suburban Rail Loop Authority.

An SRL authority spokesperson said the body was working closely with residents during construction, which was ramping up at all six station sites and the train stabling facility at Heatherton ahead of the launch of tunnel boring machines due to take place next year.

“While all dust, noise and vibration levels are well within the required limits, we are doing all we can to reduce impacts of the works, including trialling different equipment and construction methods — along with offering short term relocation,” they said.

Ms Hornstein said over the few weeks that she felt the machinery was affecting her, she discovered other residents were experiencing symptoms such as ear pain and headaches that they also associated with SRL works.

The premier said she wanted to acknowledge the experiences of the residents in Heatherton, and said a “lot of work” had been done with those affected.

“Where there is works that are happening close to homes, that it does come with a level of disruption,” Ms Allan said.

“It’s why there has been careful monitoring of the noise and there has been work with those residents — and we’ll continue to do that — understanding that they need to be supported through the construction of the project.”