However, a letter has emerged claiming the offensive menu was "a light-hearted joke" by a restaurateur.
Joe Richards, owner of Richards and Richards restaurant where the $1000-a-head function was held, says he created the menu, which included "Julia Gillard Kentucky Fried Quail - Small Breasts, Huge Thighs & A Big Red (word deleted)...", as a private joke.
Late Wednesday, the Liberal National Party released an apology letter from Mr Richards.
In the letter addressed to Mr Brough, Mr Richards said none of the mock menus were distributed on the tables or in the restaurant.
"I created a mock menu myself as a light-hearted joke, however as I said I never produced them for public distribution," Mr Richard's letter says.
"It is so unfortunate that an in-house joke between myself and my son has caused you great problems and embarrassment."
Earlier Opposition Leader Tony Abbott stood by Mr Brough, who apologised for the menu.
He said it was ridiculous to suggest he should resign over something he did not condone, authorise or write.
Both Ms Gillard and health minister Tanya Plibersek said the Liberal Party should disendorse Mr Brough, who is trying to get back into parliament via the Queensland seat of Fisher held by former speaker Peter Slipper.
After making international headlines for her misogyny speech in parliament in 2012, Ms Gillard on Tuesday reignited the gender wars with another speech describing the Liberals as "men in blue ties" who would leave women behind and make a "political plaything" of Australia's abortion laws.
"The real risk for Australia is if Mr Abbott is ever prime minister it would not be a question of what is on fundraising menus - we would see this lack of respect for women littered throughout all of his government policy documents," Ms Gillard said.
Ms Gillard also called on shadow treasurer Joe Hockey, who was the special guest at the event, to explain himself.
While he did not recall seeing the menu, Mr Hockey regarded it as "offensive and inappropriate".
However, he said Ms Gillard's focus should be on major political issues like job losses, national finances and education reform.
"Seriously, is this the biggest event in Australia today?" he asked.
Mr Hockey also said the prime minister was not exempt from making tasteless remarks and described him in parliament as a "fat man".
"The prime minster yesterday called myself, my colleagues, effectively, misogynist pigs," he added.
Mr Abbott condemned the menu.
"I think we should be better than that," he told reporters on the Gold Coast on Wednesday.
Mr Slipper, who's had his own issues with sexist language, said he was "very disappointed" by the menu but it was up to Mr Abbott to decide whether Mr Brough was a suitable candidate.
Mr Rudd, who was campaigning in Sydney, said Mr Brough had "got sprung" and should donate every dollar from the $1000 a head fundraiser to the RSPCA.
Comment was being sought from Ms Gillard, due to appear at a function in Perth.
