Associate Trade Negotiations Minister Jim Sutton announced his retirement on Monday, fuelling speculation more list MPs could be about to exit.
Prime Minister Helen Clark has publicly stated she wants some old hands to "exit with dignity" so Labour's caucus can be freshened up ahead of the next election.
Ms Beyer, believed to be the world's first transsexual MP, has previously said she would not contest that election.
Asked yesterday if she was likely to retire well ahead of the 2008 election, she said: "In my view more than likely, but that depends entirely up to how the leader wants that managed.
"It fits in with the plan I've always had regarding my life in politics, be it local government or central Government. I want to be out of it by 50 and that's not far off for me."
Ms Beyer turns 50 in November next year.
She accepted that some people would take her comments on her future with a grain of salt as she had changed her mind before.
Ms Beyer, elected MP for Wairarapa in 1999, said during her first term that she would not stand again, then changed her mind.
During her second term she again announced her retirement, and then decided she did not want to stand for the Wairarapa seat but would go on Labour's list. She was put on the list, in a reasonably safe position, and is back for a third term. Labour lost Wairarapa in the election.
She said she had made no final decision, but expected to reassess her position in the next year, once some outstanding issues were dealt with.
They included achieving clarity on the status of transsexuals in human rights law, which does not include explicit references to transgender people.
Ms Beyer's Human Rights (Gender Identity) Amendment Bill, which seeks to explicitly ban discrimination against transsexuals, is on Parliament's order paper.
The Government has been lukewarm on the bill, but Ms Beyer indicated that if it could be proved to her that transsexuals were already protected by the existing law she would consider withdrawing it.
It is understood an opinion has been sought from Crown Law.
Ms Beyer, who chairs Parliament's social services committee, said she also wanted to conclude some committee business before she left.
Timing would also depend on when the next person on the list was ready to enter Parliament, and when it suited the party.
Former MP Lesley Soper is next on Labour's list.
Ms Beyer said she was not afraid of leaving Parliament.
There was no shortage of "showbusiness" opportunities for her once she left and her status as the world's first transsexual MP meant she was in demand as a speaker internationally.
Labour list MPs Russell Fairbrother, Dianne Yates, Jill Pettis and Ann Hartley - all of whom lost their seats last year - have also been named as potential candidates to retire, but so far none has signalled a readiness to depart.
None could be immediately reached by NZPA , but Mr Fairbrother has previously said he will fight to win back Napier.
List MP Dover Samuels has said he will retire at the next election.
Helen Clark's office yesterday said she was not aware of any imminent retirements.