Australia's first minister for family violence prevention, Victoria's Fiona Richardson, is taking extended leave to battle several tumours and will not contest her key inner city seat at next year's state poll.

Ms Richardson said she had been diagnosed with multiple tumours, for which she was receiving treatment.

She will not recontest her Northcote seat at next year's election in light of her health challenges, she said.

"I intended to return to work part time next week, however my recovery is not going the way I had planned,'' Ms Richardson said in a statement.

"I remain passionately committed to the vision shared by myself and other victim-survivors to eradicate violence in the home within a generation and to end its dangerous and costly impact on families and children."

Ms Richardson took time off in 2013 to fight breast cancer.

Labor holds Northcote by 6 per cent, but is under threat from the Greens due to demographic changes.

Premier Daniel Andrews paid tribute to Ms Richardson's advocacy and her career in Parliament, which began in 2006.

"Our thoughts and prayers are with Fiona and her family, and we will do everything we can to support her during this difficult time,'' he said.

"Fiona is an unwavering advocate on behalf of victim-survivors and every Victorian touched by the tragedy of family violence.

"Fiona's work to prevent family violence continues to save lives, particularly those of women and children."

Health Minister Jill Hennessy will remain Acting Minister for Women and Prevention of Family Violence.