New research shows Labor remains on track to win the federal election as the coalition tries to defuse concerns about a controversial $80 million water buyback.
The latest Voter Choice Project results published on Tuesday have Labor leading the coalition 52.8 to 47.2 per cent in two-party terms.
The coalition's primary vote stood at 35.3 per cent, three points ahead of Labor, with the Greens polling 10.6 per cent and independents 7.8 per cent.
Notably, 54 per cent of the sample rated the government as having done a very bad or bad job, and 58 per cent said the country was on the wrong track.
As controversy about a 2017 water purchase continued to rage, Agriculture Minister David Littleproud asked the auditor-general to review taxpayer-funded water buybacks.
"I'll be asking the auditor-general to look at all purchases of all political persuasions over the last period since 2008 to make sure that we can give confidence to the community," Mr Littleproud told reporters in Tamworth on Tuesday.
Questions have re-emerged during the election campaign about a buyback of 28.7 gigalitres of water from two Eastern Australia Agriculture-owned Queensland properties, Clyde and Kia Ora, for $78.9 million.
Labor now wants an inquiry into the issue, which has put then-water minister Barnaby Joyce under pressure.
"It is now clear that there needs to be an independent inquiry into the Eastern Australia Agriculture scandal, with coercive powers so that Australians can get the truth," Labor frontbencher Tony Burke said.
Prime Minister Scott Morrison campaigned in Adelaide, where he was fighting to save Nicolle Flint's marginal seat of Boothby.
"Got any John Alexanders here?" the prime minister asked some budding tennis players, as he announced funding for oval lights, cricket nets and tennis courts.
The coalition also promised to kickstart a new Australian business growth fund with $100 million of capital it hopes banks and superannuation funds will add to, although so far only NAB is on board.
The fund would provide equity investment capital to small and medium businesses, and is hoped to mature to $1 billion within five years.
Labor leader Bill Shorten campaigned in the Nationals-held seats of Flynn and Dawson, where he promised to overhaul skilled worker visas, forcing foreign workers' wages up so locals get more of a look-in.
He also pledged to scrap the coalition's controversial $5 billion Northern Australia Infrastructure Facility and redirect the money to northern Australian gas pipelines.
Mr Shorten faced questions about the Adani Carmichael coal mine, with the opposition leader under pressure to reveal if he will review its environmental approvals if he wins on May 18.
"I'm not going to be intimidated or bullied by environmental activists or big mining companies," he told reporters in Gladstone.
"For me, it is all about the best science, the law of the land, and not creating sovereign risk."
Labor also promised to launch an inquiry into the $10 billion Melbourne to Brisbane inland rail line.
Australian Associated Press