The Electrical Trades Union has apologised for comparing Prime Minister Tony Abbott to Adolf Hitler, infuriating Jewish groups who condemned the portrayal in the union's newsletter during a campaign.

The ETU released a brief statement on Friday apologising for the newsletter and pulled the offending article from its Facebook page.

The front page of the Electrical Trades Union newsletter depicting Prime Minister Tony Abbott as a Nazi.

"The ETU sincerely and unreservedly apologises," the statement said.

"The theme of the magazine was to show the demonisation of unions has had a long history."