Forbes rich lister and serial political text pest Clive Palmer has a Parliamentary IOU.

Key points: Clive Palmer owes taxpayers almost $7,000 and he is more than 1,000 days late paying

Clive Palmer owes taxpayers almost $7,000 and he is more than 1,000 days late paying The United Australia Party has spent close to $30 million in advertising since September

The United Australia Party has spent close to $30 million in advertising since September Greens and United Australia Party members were late to repay parliamentary expense debts

The maverick Queenslander, who appears to be plotting a return to federal politics, still owes taxpayers for overspending on his entitlements when he was last in Parliament.

Worth an estimated $4.5 billion, Mr Palmer has been forced to repay millions of dollars in recent years to workers at his liquidated Queensland Nickel refinery, and the Government is seeking $70 million from him personally in a trial scheduled for July.

His newly revealed debt — almost $7,000 — can be traced back to an overspend on his staff travel budget four years ago, and is contained in documents obtained by the ABC under freedom of information.

He has had multiple opportunities to repay taxpayers. Even after his media adviser was contacted by the ABC for this story, Mr Palmer did not indicate the debt would be repaid.

Election push

The former MP has previously indicated he wished to return to Parliament in the Queensland seat of Herbert and his party has spent $27.5 million in advertising since last September, according to Nielsen.

This has included unsolicited text messages to thousands of Australians — one of them, ironically, promising to ban unwelcome messages from political parties.

However polls published in January suggested Mr Palmer had the support of just 8 per cent of voters in Herbert.

The United Australia Party website currently says the Herbert candidate is "to be announced". Mr Palmer is reportedly seeking a Senate seat.

Three years ago his Queensland Nickel refinery in Townsville collapsed with $300 million in debts, leaving some 800 without work.

Mr Palmer has said most workers have been repaid.

The Government paid $67 million to these employees under the Fair Entitlements Guarantee, which provides money for workers when companies go bust.

It is hoping to recover some $200 million from related corporate entities and $70 million from Mr Palmer in a trial set to be heard in the Supreme Court of Queensland in July.

United Australia Party spending on political advertising has been more than three times each of the major parties — some $5.5 million in the past three weeks, according to Nielsen.

Mr Palmer returned to the Forbes rich list in 2019 following a royalties win for his company Mineralogy in a matter against Chinese company Citic.

He declined to provide a comment to the ABC, but has been active in the media recently.

His Budget media release said the Budget "did not address the real economic structural changes" and called for 300kph fast trains.

Who was late to pay

As the 45th Parliament prepares to conclude ahead of the election, the ABC obtained a list of current and former MPs with unpaid debts.

These debts relate to parliamentary entitlements, and were contained in a document released by the Independent Parliamentary Expenses Authority under freedom of information laws.

The list includes:

Former Greens senator and now candidate for Brisbane Andrew Bartlett for failing to pay an invoice reimbursing the Government for airfares worth $1,879.65

Former Greens senator and now candidate for Brisbane Andrew Bartlett for failing to pay an invoice reimbursing the Government for airfares worth $1,879.65 Greens Senator Janet Rice for failing to pay two invoices for taxi fares totalling $113.50

Greens Senator Janet Rice for failing to pay two invoices for taxi fares totalling $113.50 Greens Senator Nick McKim for failing to repay a staff budget overspend of $413.02

Greens Senator Nick McKim for failing to repay a staff budget overspend of $413.02 Former One Nation and now United Australia Party Senator Brian Burston for failing to repay business class airfares for his staff totalling $9,365.02

Former One Nation and now United Australia Party Senator Brian Burston for failing to repay business class airfares for his staff totalling $9,365.02 Mr Palmer, whose debts of $6,713.15 date back to a staff travel budget overspend in 2014/15

The freedom of information process requires consultation with those whose privacy may be affected.

All but Mr Palmer repaid these debts during the processing of the request, with Senator McKim the last to do so.

"This was the result of an administrative error, and my office was not made aware of it until recently," Senator McKim told the ABC.

One political analyst had described Mr Palmer's chances in the seat of Herbert as "virtually zero". His chances in the Senate if he decides to run are likely to be higher.

Mr Palmer was widely underestimated before his success at the 2013 election, which was also marked by massive advertising expenditure.