Labor's Mulherin retires amid Qld campaign

Deputy opposition leader Tim Mulherin has quit politics during the Queensland election campaign.

The Mackay MP announced on Thursday night his decision to retire from the seat he's held since 1995, citing family and health reasons.

"My three boys have not known anything else than me in politics," Mr Mulherin told the Mackay Daily Mercury.

"My family needs me, and my wife, Erin, and my boys want to see me."

Mr Mulherin said his father, Leo Mulherin, died last month and he wanted to spend more time with his 78-year-old mother Helen.

He's also been battling health issues, he told the paper.

But he'll stay in his current roles until polling day on January 31, he said.

The move will pose problems for the Labor party, which only managed to hold onto the electorate with a 0.5 per cent margin when it claimed a meagre seven seats overall in 2012.

Opposition Leader Annastacia Palaszczuk is campaigning in Mackay on Friday and indicates she'll announce a replacement candidate soon.

Ms Palaszczuk paid tribute to her "right-hand man", describing him as a "real gentleman".

She's expected to address media later on Friday about Mr Mulherin's decision.