Mark Latham's former Labor colleagues called him the "king rat" for doing an ad for One Nation but he's now doing the same for another minor party.
The former federal Labor leader on Monday released a One Nation ad smearing Opposition Leader Bill Shorten as a liar, sparking a furious reaction from Labor figures.
But Mr Latham fired back at the critics of the robocall ad and promised to keep fighting for minor parties in the by-elections.
"I've done another one today for the Liberal Democrats this time, they want me up in Longman," Mr Latham told 2GB radio on Tuesday.
Mr Latham has been drawing a hefty parliamentary pension and working as a political commentator since leaving Canberra but he has had offers to run again for four political parties.
"I'm considering those. It's a matter for family consideration as well," he said.
Labor frontbenchers lined up to attack Mr Latham for calling Mr Shorten a liar in the One Nation ad.
"Mark Latham has become a pretty sad and pathetic figure," Labor's Jim Chalmers told Sky News on Tuesday.
Shadow treasurer Chris Bowen said Mr Latham fell out with everyone he ever worked with.
"He will go down as one of the great Labor rats of history," Mr Bowen told reporters.
Mr Latham led Labor to a crushing defeat at the 2004 federal election, giving John Howard's coalition control of both houses of parliament.
"If Mark Latham does to Pauline Hanson's vote what he did to Labor's vote, I'm not at all worried," Labor deputy leader Tanya Plibersek told reporters.
Mr Shorten brushed off the attack as "a sideshow".
"Mark Latham used to be someone, he's not anymore," he told reporters in Tasmania ahead of the by-election in Braddon.
Foreign Affairs Minister Julie Bishop pointed out the irony of a man Labor previously proposed as an alternative prime minister calling Mr Shorten a liar.
Liberal Democratic senator David Leyonhjelm said Mr Latham was a paid-up member of his party.
"He's still not sure that he wants to be a politician again. So that's the threshold test," Senator Leyonhjelm told AAP.
Former ALP powerbroker Graham Richardson confronted Mr Latham on Sky News on Monday night, calling him a "king rat".
"It's a tragedy and it's sad, Mark," Mr Richardson said.
Senator Hanson said it would be fantastic to have Mr Latham beside her in parliament but has denied any approach has been made to have him join One Nation.
"I think someone of Mark's knowledge, experience and willingness to speak against political correctness is much needed," Senator Hanson said on Monday.
In the robocall, Mr Latham blamed Mr Shorten for causing the by-election in the Labor-held seat of Longman because he mishandled the federal dual-citizenship crisis.