Deputy Opposition Leader Tanya Plibersek is certain Clive Palmer will not preference Labor amid reports the controversial businessman is on the verge of doing a deal with the coalition.
Mr Palmer's United Australia Party is polling well in some key marginal contests, making his how-to-vote cards potentially crucial at the May 18 election.
"I'm very certain that Clive Palmer won't be preferencing Labor, he's never voted with us in his life and he's made that very clear," Ms Plibersek told ABC News Breakfast on Wednesday.
The coalition is close to striking a deal with Mr Palmer, which could deliver him a Senate spot and help the coalition's fortunes in Queensland lower house seats, The Australian reports.
"Scott Morrison is playing off One Nation against Clive Palmer," Ms Plibersek said.
The senior Labor figure said she would be surprised if UAP played a major part in the Townsville-based seat of Herbert, which the opposition holds with a wafer-thin margin, given his treatment of workers in the area.
"I would think the workforce of Townsville would remember better than most how disappointing Clive Palmer has been," Ms Plibersek said.
"He loves to make big promises and he leaves behind a trail of destruction, frankly."
How-to-vote cards will need to be finalised in time for early voting which starts on April 29.
A Newspoll released on Tuesday shows United Australia Party holds between five and 14 per cent of the primary vote in the marginal seats of Herbert (Queensland), Deakin (Victoria), Lindsay (NSW) and Pearce (WA).
Mr Palmer has ploughed millions into an advertising blitz with voters inundated across a range of media.
Australian Associated Press