Former Labor leader Mark Latham has joined Pauline Hanson's campaign in the Longman by-election, urging voters to retaliate against his former party.

Key points: In a pre-recorded call, Mark Latham says the only reason for the Longman by-election is because Bill Shorten "lied"

In a pre-recorded call, Mark Latham says the only reason for the Longman by-election is because Bill Shorten "lied" He does not ask voters to endorse One Nation, but the call is sponsored by Pauline Hanson

He does not ask voters to endorse One Nation, but the call is sponsored by Pauline Hanson Mr Latham joined the Liberal Democrats last year, prompting the Labor Party to declare it would never let the former leader rejoin

In a pre-recorded "robocall" message being issued in the marginal Queensland electorate, Mr Latham criticised Opposition Leader Bill Shorten for his "dishonesty".

"He just lies and lies and lies," Mr Latham said.

"The reason we're having a Longman by-election is because Shorten lied about the citizenship of his Labor MPs."

Four of the five by-elections being held on July 28 were called because Labor MPs and the Centre Alliance's Rebekha Sharkie were dual citizens and not eligible to have been elected.

Labor figures privately say they are nervous about the party's prospects in Longman, which is north of Brisbane.

It holds the seat with a narrow margin of 0.8 per cent.

Monday's robocall is personally authorised by Senator Hanson herself, but Mr Latham does not specifically endorse One Nation, instead urging voters to support minor parties.

"Whatever you do, don't reward Shorten's dishonesty, don't vote Labor," he said.

"Please support minor parties and independents to shake up the system and put some honest politics back into Canberra."

Hanson and Latham a 'chaotic combination'

The ABC understands One Nation is considering rolling out the call in other electorates where by-elections will be held on July 28.

The party is not running candidates in any of those seats, but Labor is contesting all of them.

Mr Latham, who has been teasing about a political comeback, has not joined One Nation as a member.

He announced he had signed up with the Liberal Democrats last year.

That move prompted Labor to reveal it would never let him rejoin the party.

ALP president Wayne Swan described Mr Latham as "someone who ratted on battlers and working Australians years ago".

"So it's no wonder he's teamed up with Hanson," Mr Swan said.

"This is the same bloke who had a go at domestic violence campaigner Rosie Batty and can now be found in his basement making YouTube videos," he said.

Mr Swan called Mr Latham and Senator Hanson a "chaotic combination".

"No amount of stunts from Pauline Hanson and her mate Mark Latham can hide the fact that she votes with Malcolm Turnbull and the top end of town 90 per cent of the time down in Canberra," he said.

Queensland ALP senator Anthony Chisolm said on Twitter "hopefully he drives the One Nation vote into the ground like he did the Labor vote in 2004".

Mr Latham led the Labor party to the 2004 election against John Howard but the party lost.

He quit Parliament in early 2005.