Malcolm Turnbull and Bill Shorten are toughening their warnings against minor parties as the election campaign reaches the halfway point, with both sides yet to break through with voters.
The prime minister has slammed the Greens, independents and the Nick Xenophon Team, declaring a vote for anyone but the coalition is a vote for chaos.
The opposition leader also turned on the Greens, and the minor party's declaration that the Labor and Liberal parties are working on preference deals to lock them out.
With four more weeks to go till the July 2 election, polls show the big parties neck and neck with, variously, Labor just in front, the coalition just in front or the two equal on 50-50.
The latest Fairfax/Ipsos poll shows Labor leading the coalition 51-49, in line with Newspoll and Essential polls from earlier this week, adding to fears of another hung parliament.
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Polls also show substantial support for the Greens and Xenophon team.
That's especially so in South Australia where the Nick Xenophon Team could take two Senate spots and possibly a lower house seat.
In Adelaide on Saturday Mr Turnbull urged voters not to go there.
"A vote for anyone other than my coalition team is a vote for chaos," he told a group of Liberal supporters.
"Every single vote for Nick Xenophon, the Independents, the Greens or Labor, brings us closer to Bill Shorten and the Greens running Australia. So now is not the time for a protest vote or a wasted vote."
Mr Shorten accused the Liberals and Greens in Victoria of continuing to plot a preferences deal that would damage Labor's prospects in seats such as Batman and Bruce.
However, the Greens have posted on their website a vow that they will "never preference the Liberals above Labor".
The party's only lower house MP Adam Bandt has accused Labor and the Liberals of working on a preference deal to stop the Greens in seats such as Batman and Wills in Melbourne and Grayndler and Sydney.
"If the Greens are unhappy, perhaps they should buy a mirror and look into that to see what the real problem is," Mr Shorten said.
He said the Greens had been "pretty naughty" over the past three years, citing instances where Greens senators sided with the government, including changes to Senate voting arrangements and political donations.
Pauline Hanson's One Nation party may emerge as another player in the Senate. The Queensland firebrand is increasingly confident of re-entering parliament - even if the prime minister doesn't want her there.
But she is prepared to work with whoever is in government.
"I will support anyone on any legislation or policy as long as I believe it is right for the Australian people, and for the future of this country," she said.
Mr Turnbull campaigned in Adelaide on Saturday, announcing funding for a sports oval and a $24 million scholarship program to train 1200 of the state's best and brightest for careers in defence industry building the nation's $50 billion new submarine fleet.
Mr Shorten was campaigning in his own Melbourne seat of Maribyrnong which he holds with a margin of more than 20 per cent.
Visiting a local market, he encountered a woman who inquired about pre-poll voting, indicating his big challenge may not be to convince voters to pick Labor but ensuring they know where to vote.
Mr Shorten later launched Labor's $160 million arts policy at the Malthouse Theatre, declaring arts may not decide the election but they could define a nation.
For many voters the opportunity to take part in the only poll that counts comes quite soon with pre-poll voting opening in 10 days, prompting Mr Turnbull's warning.
The ALP needs a net gain of 21 seats to take government.
