Bill Shorten has accused Malcolm Turnbull of arrogance about the coalition's election victory hopes, as the prime minister homed in on Labor's links with the Greens.
Opinion polls and betting agency figures point to a swing against the coalition, strongest in Western Australia, but not enough to unseat the Turnbull government on July 2.
Campaigning in Perth, where he launched several candidates' campaigns, Mr Turnbull confidently boasted of victory.
"We are confident that Australians will return us to government, but it is their decision," Mr Turnbull said.
Mr Shorten, also on the election trail in Perth, said Labor was in the election to win.
"I think it is the height of arrogance to tell Australians that their vote doesn't matter because he's decided that he will win," Mr Shorten said of his opponent.
The coalition on Wednesday launched a new advertisement highlighting the "greening of Labor" and the potential for a minority government similar to that formed in 2010.
Asked whether it amounted to a desperate scare campaign, Treasurer Scott Morrison described it as a "truth campaign" showing what would happen if 2010's "caravan of chaos" returned to the road.
"A Greens-Labor-independent government is a very real prospect at this election," Mr Morrison told reporters in Sydney.
Mr Shorten said Mr Morrison should "spend more time on his day job as treasurer than his night job as amateur YouTube video producer".
Labor is expected to fend off the Greens in a number of inner-city seats, with its task made easier by Mr Turnbull making a captain's call not to preference the minor party anywhere.
Analysts expect the Greens to win only one lower house seat - Melbourne - but come close in another Victorian seat, Batman.
Mr Turnbull said the Greens were pulling Labor to the left like a magnet.
"The old Julia Gillard-Bob Brown-Tony Windsor-Rob Oakeshott band (is) trying to get back together," he said.
With less than three weeks to go until election day, Mr Turnbull has spent three out of four days of the campaign defending coalition seats.
Mr Shorten has spent 60 per cent of his time targeting non-Labor seats.
Both leaders have spent well over half of the campaign in Queensland and NSW.
One bookmaker has the odds of a coalition win at $1.17, compared with $5 for Labor, the shortest since the campaign began.
Punters are steering away from a hung parliament, with odds drifting from $3.75 out to $4.25.
