John Howard has added star power to Denis Napthine's struggling election campaign, but another prime minister has favoured brute force to try to help the Victorian coalition over the line on Saturday.
Prime Minister Tony Abbott has threatened to withdraw billions of dollars in infrastructure funding from the state if Labor tears up the contract for the controversial East West Link.
"I want to make it absolutely clear to the people of Victoria that the $3 billion the commonwealth government has committed to this project is for one purpose and one purpose only - and that is to build the East West Link," Tony Abbott wrote in an open letter to Dr Napthine and Opposition Leader Daniel Andrews.
Mr Abbott, who has not been seen in Victoria for three weeks, said that money would not be allocated to any other Victorian project.
However, Mr Andrews said he would try to sit down with Mr Abbott to discuss "how we might all work together to help him deliver on his commitment to be the infrastructure prime minister".
Federal Liberal MPs used question time in Canberra to further the attack on Dr Napthine's behalf, with Treasurer Joe Hockey reinforcing Mr Abbott's warning and adding 7000 jobs would lost if the East West Link was axed.
"Victorians will lose out, not only on the $3 billion from Canberra for new roads, they will end up paying more than $1 billion a compensation to a building and construction company for a road that was never built," he told parliament.
Federal Justice Minister Michael Keenan called into question Mr Andrews' ties with the CFMEU.
He said the union faced allegations at the royal commission of blackmail and extortion, and "rubs shoulders with criminals, members of the Comancheros bikie gang, (and) underworld heavy George Alex".
"Victorian Opposition Leader Daniel Andrews, if he were to win the election on Saturday, he will have been installed by the CFMEU, financed by the CFMEU - the one who brung him will be the most notoriously corrupt union in the country," Mr Keenan told parliament.
Mr Andrews' office refused to respond to the allegations, describing Mr Keenan as being from Western Australia and irrelevant.
Dr Napthine earlier on Wednesday had to fend off friendly fire from predecessor Jeff Kennett who gave the government's election campaign a score of eight points out of 25, only a little more than the five points he allocated to Labor.
Shadow attorney-general Martin Pakula said he wouldn't expect a former Liberal premier to highly rate the Labor party, but it was extraordinary he'd given the coalition government a "fail".
But Mr Howard gave Dr Napthine a big tick during a visit to a shopping centre in the Liberal-held seat of Ringwood, a suburb affected by the East West Link.
"Denis Napthine has presided over the best running economy of any of the states of Australia," he said.
"The people of Victoria, I hope, will keep that in mind and won't take the risk of handing the management of the Victorian economy to a man who's bound hand and foot to the radical left wing CFMEU."
If opinion polls are correct, Labor will win Saturday's election, making the coalition a one-term government.
Meanwhile, Labor will on Thursday finally release the costings for its election promises.
