One Nation’s candidate in the federal Queensland seat of Longman says Labor is behind a smear campaign claiming he owes tradies tens of thousands of dollars.

Building subcontractors claim Matthew Stephen’s former company, Aus Tile Qld Pty Ltd, has left a trail of debts and say voters shouldn’t support him in Saturday’s crucial by-election.

Gold Coast subcontractor Matthew Young has told the Nine Network he’s owed about $6500 from a Darwin project he worked on with Mr Stephen in 2014.

He says his brother is owed about $11,000, and he’s aware of half a dozen others who are also owed about the same amount.

“Why should a guy like this be in parliament? If he’s going to do this to us, what’s he going to do when he’s in parliament,” Mr Young said on Tuesday.

Mr Young admitted he’d been approached by Labor, which is fighting to hold onto Longman, and that the party had asked him about his experiences with Mr Stephen, but he said the party hadn’t offered him any guidance.

The subcontractor said Mr Stephen had repeatedly promised to pay his debts but then never did, forcing him to engage a solicitor to try to recover the money.

“The solicitor told us he was going to turn it into a $1 company, sell it and not have to pay all of us, which is basically what he has done,” Mr Young said.

He’s not the first to claim Mr Stephen has unpaid debts.

Stavros Mostris, who leased a property to Mr Stephen’s former company, has previously told The Courier-Mail he’s owed thousands in unpaid rent, and Darwin tiler Nick Fullerton claims to have been underpaid on three jobs for the company.

Mr Stephen has denied those claims.

In a Facebook post and video on Monday, the candidate said he was the victim of an ugly political attack that showed how scared Labor Leader Bill Shorten was of losing Longman to the conservative vote.

“It is nothing more than political bastardry and I lay it solely at the feet of the Labor party,” he said, adding it was “fake news that I owe some money”.

“I know we’ve got you scared Bill.”

Mr Stephen can’t bank on any further help on the hustings from One Nation leader Pauline Hanson, who has gone on a holiday to the UK just days out from the by-election.

She has told The Courier-Mail she’ll be supporting her candidate from afar, and that she booked the holiday in February because she was worn out.

-AAP