Queensland Labor's longest-serving state MP Jo-Ann Miller has resigned, effectively immediately, amid escalating tensions within the Labor party.

It comes three days after Ms Miller publicly acknowledged growing tensions between herself, some backbench MPs and Labor's senior leadership amid claims of bullying.

Ms Miller, who this month celebrated 20 years as the Member for Bundamba, broke down as she resigned in Parliament this morning, citing a "health scare".

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"Mr Speaker, I will now come up to you and hand to you a signed copy of my resignation," she said.

After delivering her letter to the Speaker, Ms Miller lost her footing walking down from the Chair and was caught by former foe and Liberal National MP Jarrod Bleijie.

She was told to leave the House minutes after her resignation given she was no longer an MP.

More than a dozen MPs, many from the Opposition, hugged Ms Miller as she made her way out of the House.

The Government frontbench stayed seated and did not approach Ms Miller to wish her well.

In the letter, Ms Miller said she was the "last of a generation of Labor MPs in Parliament".

"We will never see their like again in this House," she wrote.

The decision to leave comes after recently having an operation to remove a tumour.

"Incidents like these make you reflect on your life and this has played a part in my decision to leave my role."

Ms Miller had once served as Police Minister during her 20-year career. ( AAP: Darren England )

Won't run for Ipswich Mayor

The Ipswich MP holds her seat by one of the strongest of margins in the House, at more than 70 per cent on a two-party preferred basis in an electorate, which encompasses traditional Labor suburbs of Goodna, Redbank and Collingwood Park.

Ms Miller was one of the outspoken critics against the former Ipswich City Council under former mayor Paul Pisasale.

And despite months of speculation, Ms Miller confirmed today that she does not intent to run in the upcoming local government elections, either for Ipswich mayor or as a role as a councillor.

Ms Miller resigned today after 20 years in the job. ( AAP: Darren England )

"It is time for me to move onto whatever is in God's plan for me," she said.

"My family has put up with enough and I will not put them through it again in another role.

"However I would like to thank our community for their great outpouring of support had I wished to nominate, and their trust in me."

Ms Miller's tensions with the Labor party's leadership stems back to 2015 when she was forced to resign as police minister during a shake-up of the Palaszczuk ministry.

She was also the only Labor MP to vote against the decriminalisation of abortion in 2018.

The Labor stalwart and other Labor backbenchers have been agitating to have Ms Trad removed from Cabinet, fearing electoral damage caused by Deputy Premier Jackie Trad's controversial investment house purchase.

Queensland Premier Annastacia Palaszczuk has thanked Jo-Ann Miller and Jann Stuckey for their services to Parliament. ( AAP: Darren England )

Her sudden resignation will force the second by-election before the October state election, following the resignation of Opposition MP Jann Stuckey in the seat of Currumbin in January.

Premier Annastacia Palaszczuk said it was likely a "tough decision" for both Ms Miller and Ms Stuckey.

"I'd like to thank Ms Miller … for her longstanding service to this Parliament," Ms Palaszczuk said.

"I wish both the Member for Bundamba and the Member for Currumbin all the very best for their future."