A company representing a comedian has apologised to Opposition Leader Tony Abbott and his chief of staff Peta Credlin for what Prime Minister Julia Gillard has described as an "offensive" joke at a union dinner in Canberra.
Manic Studios said in a statement it unreservedly apologised to Ms Credlin and Mr Abbott for the joke made at the Construction Forestry Mining and Energy Union dinner at Parliament House on Wednesday.
"The joke was a last-minute inclusion and crossed the line," spokesperson Piers Grove said.
"We did not run the joke past anyone. Nobody from the CFMEU or the Labour party or anyone else in attendance at the dinner knew of the joke until it was told.
"The poor reaction the joke received is testament to the fact that we exercised poor judgment.
"We unreservedly apologise to all parties for any offence."
Ms Gillard, who was at the dinner but was not present when the joke was made by comic character Allan Billison, contacted the union on Thursday morning to tell them she was offended by it.
The comic character is spearheading a satirical union campaign, Fair Go For Billionaires.
"Clearly there is no place for offensive comments of this nature," Ms Gillard said.
The furore comes just days after Ms Gillard accused Mr Abbott in parliament of being sexist and misogynistic.
Health Minister Tanya Plibersek, who was also at the function, said the remarks were "out of order".
"Earlier today I have rung two of the senior officials at the CFMEU and said that we leave family out of our debates here in Canberra, that it's inappropriate," she told reporters.
"I wanted the two officials to pass on my disappointment to the comedian for making remarks that I think, if they were reported, would be distressing to the family of the leader of the opposition."
Housing Minister Brendan O'Connor, another minister at the function, said the joke was "offensive".
Shadow treasurer Joe Hockey said Labour had "some explaining to do" over the remarks.
"They are trying to set a new benchmark - they can't hold that benchmark themselves," he told reporters.
"What a surprise."
Trade Minister Craig Emerson said he had left the function shortly after the joke was told.
"The Labour party to a person and the union have quickly and swiftly and unequivocally condemned those comments," he told Sky News.
However AAP is still waiting for comment from the CFMEU.