Tony Abbott and Bill Shorten will plead today with the WA public to stick with the coalition and Labor amid fears the Palmer United Party's wall of advertising is wooing over disengaged voters.
The Prime Minister and Opposition Leader are in Perth today, with concerns in both major parties about the results in Saturday's Senate re-run election.
Internal and public polling suggests PUP's lead candidate Dio Wang, who won a spot in the original contested count of WA's Senate ballots, is collecting enough support to guarantee him a position in the new Senate, which sits from July 1.
His success could put at risk the Liberal Party's third candidate, Linda Reynolds, or Greens Senator Scott Ludlam. It would also make life hard for Mr Abbott in getting legislation through the Senate where, even after this weekend's election, the Government will not have a majority.
The major parties have been stunned by the size of PUP's advertising campaign in the lead-up to Saturday's poll.
A PUP representative failed to attend the weekend's candidates' forum - organised by _The West Australian _, the Seven Network and the Australian Institute of Management WA - where a range of issues at the heart of the election campaign played out.
Ebiquity, an advertising monitoring firm, estimates PUP has spent 10 times more than Labor and 20 times more than the Liberals on television advertisements.
Mr Abbott yesterday made special reference to the threat posed by micro-parties and their preference deals. "If you vote for a minor party candidate, you just don't know who you will end up with," he said.
"So there is only one certainty in this election - only the Liberal Party has a plan to help Western Australia build a stronger economy with more jobs and less pressure on families."
Apart from attending a major fundraiser in Perth tonight, Mr Abbott will head a Cabinet meeting tomorrow. Cabinet ministers will spread out across the city in the next few days to push the coalition's message.
One of the biggest fears for Labor is that voters may not turn out in sufficient numbers to ensure the election of its number two candidate Louise Pratt.
Labor is especially concerned about the young voter turnout on Saturday, given that 30 per cent of people under 30 did not vote in the recent Griffith by-election in Queensland.
"My message this week is turn up on Saturday and have your say," Mr Shorten said.
The ALP will focus on education and health and also tap into what it perceives as the weakness of the Barnett Government.
At the candidates' forum, Defence Minister David Johnston hammered the Liberal Party's election messages, claiming the carbon tax was killing WA.
Senator Pratt used her time at the forum to attack the Abbott and Barnett governments over cuts in education, while Senator Ludlam called on voters to think about future generations when casting their ballot.