Australian Greens leader Christine Milne says sexism is behind accusations about Prime Minister Julia Gillard's past work as a lawyer.

Senator Milne said there was a "group of older, white men in Australia" who did not like the idea that at last women were coming into their own.

"They've never accepted the legitimacy of a woman as a prime minister and they are kicking back in every which way they can," she told reporters in Canberra on Tuesday.

She was commenting on the controversy surrounding the legal advice given by Ms Gillard to AWU officials, while she was a lawyer in the 1990s.

Ms Gillard on Monday held an extended press conference to tackle the allegations, stating the coalition was running a "sleaze and smear" campaign.