“It started being initially termed as being the top-20 marginals,” he said.

Mr Boyd said the office of the Prime Minister was also involved in the “canvassing” of potential projects.

The contact person in the Prime Minister’s office was the same involved in the contentious sports grants program.

In Parliament,Labor pressed Mr Morrison on who compiled the “top-20 marginals” seat but the Prime Minister handballed the question to Urban Infrastructure Minister Paul Fletcher.

He did not address the issue,instead saying Mr Tudge was legally entitled to allocate money.

“I will tell you who made the decision,the minister of the day made the decision. And the minister of the day had authority,” he said.

Labor’s urban infrastructure spokesman Andrew Giles said the entire situation was a farce and the Prime Minister needed to be upfront about the program.

“If[Mr Tudge] didn’t know about this list,there is only one person who could have known,Mr Morrison,the Prime Minister,” he said.

Labor won a vote in the Senate ordering the government to produce the top-20 marginals list,a map of Australia setting out which electorates would have projects within the Urban Congestion Fund,and spreadsheets shared between Mr Tudge’s staff,the Prime Minister’s office and the department.

The government is supposed to hand over the documents by Monday morning. However,historically the minister usually tables a short statement explaining why they can’t do that instead.

The vote narrowly passed 14-13,with a reduced number of senators in Canberra due to the coronavirus lockdowns. “I don’t know how we won that,” Labor’s finance spokeswoman Katy Gallagher said afterwards.

Senator Gallagher also introduced a bill to the Senate that would require faster public reporting of when ministers approve grants in their own electorate or make decisions that go against departmental recommendations.

Former Victorian Supreme Court judge David Harper,QC,said last month the scheme was “on any appropriate definition”an example of corruption.

Mr Tudge said the car parks were chosen on the basis of need. Two of the projects,Ferntree Gully and Boronia,were in Mr Tudge’s electorate of Aston.

He said the Auditor-General had found the decisions on the car parks were legal.

“The Auditor-General also said they were all lawfully based,33 of them were ticked off by the department for coming up for decision. We took those to the Australian people and the Australian people voted for them,” he said.

Mr Tudge said the Coalition had sunk $9.1 billion into three “mega” projects across western and north-western Melbourne which were Labor-held seats. He nominated the planned Geelong fast rail project – which the Coalition promised at the 2019 election as part of its efforts to retain the marginal Liberal-held seat of Corangamite – as an example.

Mr Tudge,who said Labor’s own car park fund had promised projects to either Labor-held seats or those it was targeting at the last election,said the program was all about boosting demand for suburban rail.

“Our aim was to boost capacity right across particular lines,” he said.

“If you can boost capacity in one location it supports capacity further down the track. I had representations as much as anyone did across Melbourne,that people go to commuter car parks in the morning,find that the first one is full so what do they do,the drive to the next one. The next one’s full so they drive to the next one. The next one’s full and it keeps on going.”

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