Key Labor figures condemned on Thursday a joke that poked fun on Opposition Leader Tony Abbott and his top aide, Peta Credlin, declaring in unison that the remarks were "sexist, offensive and inappropriate."

Prime Ministers Julia Gillard told reporters today in Canberra that officials of the Construction Forestry Mining and Energy Union (CFMEU) had erred in allowing the "deeply offensive" comments to be made by the union group's hired comedian.

The comedian, who Fairfax Media has identified by his alias Allan Billison, appeared last night in a dinner hosted by the CFMEU at the Parliament House.

Mr Billison was around to deliver some light moments and pitched for the political drive of Fair Go Billionaire, a self-decaled profit organisation "dedicated to helping the underdog," The Sydney Morning Herald reported.

Mr Billison's time on stage drew laughter from the obviously Labor-dominated guests, including the comic's 'funny comments' that took Mr Abbott and Ms Credlin as subjects, according to media reports.

Prominent Labor officials were watching when the questionable lines were delivered but Ms Gillard said she already left the function and learned only today about the tasteless remarks, which she stressed "should never had been made."

The prime minister disclosed she already spoke with CFMEU National Secretary Michael O'Connor to clearly express her displeasure over the matter.

"In those circumstances, as soon as I possibly could I rang the national secretary of the CFMEU and indicated I felt these comments were offensive," Ms Gillard was quoted by The Australian as saying.

Treasurer Wayne Swan, who The Herald said spoke after Mr Billison's moment on stage, was equally critical of the joke, which he labelled today as "clearly very inappropriate and offensive."

"There's no place for those kinds of comments and I made that clear to the union this morning," Mr Swan was reported by News Ltd as saying today.

One of the cabinet officials, Trade Minister Craig Emerson, who heard the remarks, told Sky News in an interview that CFMEU's comic guest had uttered offensive and sexist joke, which he noted "no one knew . . . was coming."

However, Dr Emerson quickly stressed that "the Labor party to a person and the union have quickly and swiftly and unequivocally condemned those comments."

In a statement, Manic Studios, the company who hired Mr Billison for the CFMEU event, has admitted that the comic's piece was not vetted and the unleashed joke "was a last-minute inclusion and crossed the line."

"We did not run the joke past anyone. Nobody from the CFMEU or the Labor Party or anyone else in attendance at the dinner knew of the joke until it was told," Manic Studios spokesman Piers Grove was reported by ABC as saying.

The company added that it already extended an "unreserved apology" to Ms Credlin, conceding that "the poor reaction the joke received is testament to fact that we exercised poor judgement."

Meanwhile, considering Labor's latest moral crusade, the government indeed should feel accountable for the irresponsible comments, according to Shadow Treasurer Joe Hockey.

"They're trying to set a new benchmark, they can't hold that benchmark themselves - what a surprise," Mr Hockey told reporters.

The new controversy erupted as Labor ramped up its efforts to tackle what it characterised as Mr Abbott's misogynist and sexist attitude towards the prime minister and other women who exude great power and capabilities.