Home Affairs Minister Peter Dutton has urged Bill Shorten to denounce a union how-to-vote card which puts a white supremacist ahead of the Liberal National Party.
The Queensland Council of Unions has authorised election material in the Longman by-election which urges voters to put the LNP's candidate Trevor Ruthenberg last.
However, this would mean putting Australia First Party candidate and white supremacist group stalwart Jim Saleam ahead of Mr Ruthenberg.
The Labor how-to-vote card puts Mr Saleam last and the party has been critical of Pauline Hanson's One Nation which has urged preferences for Mr Saleam ahead of Labor's Susan Lamb.
Campaigning in Longman on Friday, Mr Dutton said Mr Shorten should stand up to the unions.
"He has the ability to stand up to the unions and tell them today they should put Trevor Ruthenberg ahead of the white supremacist candidate," Mr Dutton said.
The QCU's Ros McLennan said the LNP was the real threat to working families in Longman.
"This federal LNP government is all about wrong priorities and the by-election is a referendum on priorities that matter for working people," she told AAP on Friday.
She said while Mr Saleam's politics were abhorrent, he had no chance of gaining the support of voters in Longman.
"Not withstanding what I think about him, in terms of who can do the most damage to the people of Longman it's the LNP."
The union's campaign was independent of any political party, she said.
Mr Saleam, a founder of National Action, has served jail sentences for insurance fraud and organising a shotgun attack on an African National Congress representative.
He said on his Facebook page his views were based on the "radical-nationalist tradition and historical labourism" and two key issues for his party were "Chinese imperialism and the recolonisation of the country".