THE Australian Christian Lobby (ACL) is considering an offer from beyondblue chairman Jeff Kennett to speak at its national conference after Prime Minister Julia Gillard pulled out.

Ms Gillard yesterday withdrew from speaking at the October conference in Canberra, citing "offensive" comments by ACL leader Jim Wallace on homosexuality.

Mr Kennett, one of the founders of the depression advocacy group, has written to Mr Wallace offering his services, saying it was important such comments didn't go unanswered.

"I challenge the Australian Christian Lobby to allow me to speak at their national conference in October to put a more temperate, and I suspect, a more Christian view because nowhere in the Bible do I find the act of discrimination acceptable," the former Victorian premier said in a statement on Friday.

An ACL spokesman told AAP the organisation had received Mr Kennett's letter and would reply in due course.

But he questioned Mr Kennett's decision to make his offer public.

"It's an unusual thing to then issue a media release saying you've made that offer," he said.

Ms Gillard had said it would be inappropriate for her to go after Mr Wallace this week compared the health effects of smoking with that of being gay.

"Although everyone is entitled to their own view, these statements ... are totally unacceptable," she said in a statement yesterday.

Earlier this week, the beyondblue depression advocacy group launched a campaign to raise awareness of mental health problems faced by people whose sexuality doesn't fit in with the mainstream.