Morrison was campaigning in Melbourne on Friday, continuing to spruik federal budget initiatives and attack Labor as unfit for office.

“We don’t claim to be perfect. But what we do claim is the results of our economy, the results of our national security and the plan for the future,” he told Melbourne radio 3AW.

“No one knows who (Labor leader) Anthony Albanese is. They don’t know what he’s going to do. He’s had three years to tell the Australian people what he’s going to do – he hasn’t.”

Deputy Prime Minister Barnaby Joyce was also on the attack, tying Labor to the Greens and saying they’ll increase taxes in Central Queensland.

Joyce turned the first sod on the Olive Downs coal mine – located around 200 kilometres inland from Mackay – promising to underpin the regional Australian economy.

“Guess where the businesses are that are going to get a new tax? Right here and in North Queensland – not Sydney,” he said.

His attack follows Labor seeking to reduce the safeguard mechanism from 100,000 tonnes of carbon dioxide a year, which would make heavy emitters pay more for their emissions.

Defence Minister Peter Dutton also accused Labor of being tax happy and imploring voters to continue to put their trust in the government against coming economic headwinds.

“You don’t want to risk change of government in that circumstance,” he told the Nine Network.

But Labor Deputy Leader Richard Marles hit back, saying the government had doubled Australia’s debt before the pandemic began and branded the budget’s “stand out stat” as being nine years of stagnant wage growth.

“We’ve had record low wage growth in Australia. That’s because under this government productivity has fallen through the floor,” he told the Nine Network.

“Cost of living is a real issue – the crunch is there because wages are stagnant. That’s why we’re taking measures like making childcare more affordable, making TAFE free, trying to lower power bills.

“At the end of the day we have to get wages going.”

But the Liberal election campaign could be derailed before it starts as the prime minister awaits the result of a special leave application to the High Court by expelled NSW Liberal member Matthew Camenzuli.

Camenzuli is challenging the federal executive’s ability to intervene in the selection of NSW candidates for the election, due to be held on May 14 or 21.

A federal panel comprising Morrison, NSW Premier Dominic Perrottet and former party president Chris McDiven stepped in to save ministers Sussan Ley and Alex Hawke, and backbencher Trent Zimmerman from being dumped as candidates.

The High Court will decide whether to allow special leave to hear the application at 4pm on Friday.

A successful court action could also put nine other NSW Liberal candidate selections in jeopardy.

A senior Liberal figure told AAP this would effectively mean “game over” for the Morrison government.

The coalition is well behind Anthony Albanese’s Labor team in published opinion polls.

An average of polls, published by election analyst William Bowe, puts Labor on 55.3 per cent of the two-party preferred vote – a 6.8 per cent turnaround on the 2019 election result.

Morrison’s pitch centres on the government’s economic and health efforts in getting through and beyond the Covid-19 pandemic.

“My opponent in this election, Anthony Albanese, is a blank page,” he told reporters on Thursday.

“And at a time of great uncertainty … not just in the economy, but also in terms of national security, a blank page is no answer to the problems that Australians face.”

Albanese, who will be in Adelaide on Friday, summed up his platform on Thursday as seeking “a better future for Australia where no one is left behind and no one held back”.

He points to infighting within the Liberals as a sign the government is more concerned with its own survival than issues of importance to Australians.