West Australian Senate hopeful Rod Culleton has failed to convince a Perth magistrate to postpone his stealing trial because he needs to be in Canberra to prepare for Federal Parliament.

Culleton, the lead WA candidate for Pauline Hanson's One Nation party, is due to face a four-day trial in Perth Magistrates Court in August over allegations he stole a $27,000 hire car last year.

The alleged theft happened during a heated clash when he was trying to stop receivers repossessing a friend's farm.

Culleton's laywer Gerald Yin requested the case be adjourned because his client "appeared quite certain" to win a place in the Senate and he wanted to be in Canberra by next week to make preparations for Parliament, which starts sitting on August 30.

Mr Yin said Culleton had not foreseen winning a position in the Senate and had only become aware of his likely victory in the past week or so.

Mr Yin also said Culleton's "numerous competing interests" would make it difficult for him to prepare for the trial and would result in "significant prejudice to his legal position".

Magistrate Peter Malone rejected the adjournment application, saying Culleton had nominated himself for the election despite knowing about the date of the trial since March this year.

Mr Malone said while it was "admirable" he wanted to be prepared, there was no indication when Culleton would formally be required to be in Canberra, and his plan to be there by next week seemed to be a "timeframe of Mr Culleton's own making".

The four-day trial is scheduled to finish on August 25, and Mr Malone said that would be enough time for Culleton to make it to Canberra to prepare for Parliament if he secured the seat.

If convicted of the charge, Culleton could be disqualified from taking office.

He is also appealing against a New South Wales larceny conviction.

That case relates to a dispute with a tow truck driver who was attempting to repossess a vehicle.