Former Speaker Anna Burke will quit politics at the next election.
The Labor MP who has held the Victorian seat of Chisholm for 17 years said she can't guarantee giving the job 100 per cent anymore.
"I'm leaving because you have to go sometime and I want to go before I resent doing a job I love and no longer cherish every moment in my electorate," she revealed in a statement on Wednesday.
With "mixed emotions", Ms Burke said the time had come, but not because she was running away from the prospect of facing a Malcolm Turnbull-led coalition.
Nor because she wanted to look after her family.
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"Maddie and John are no longer young, and I hope I have not sacrificed my family for my job," she said.
Ms Burke described serving the people of Chisholm as a "complete joy and honour".
"The seat of Chisholm is not mine ... it belongs to the people who call the suburbs of Chisholm home and they have been very gracious to elect me six times to represent them in parliament," she said.
The former Speaker, who served from October 2012 until August 2013, said she would help the next Labor candidate campaign in the seat.
Opposition Leader Bill Shorten paid tribute to Ms Burke, noting her remarkable service to Labor.
He singled out her advocacy for action on climate change and the humane treatment of refugees.
As the member for Chisholm, she upheld the tradition of Caroline Chisholm, as a fearless and tireless advocate for the rights of asylum seekers, Mr Shorten said in a statement.
"Her unflinching dedication has earned her deep respect both inside and outside our party," he said.
Mr Shorten said Ms Burke was a skilful, impartial and patient Speaker during a fractious and contested parliament.
