Lady Hermon said the role would not suit her temperament
North Down MP Lady Hermon has told BBC News that she was asked by senior Labour Party figures to be a candidate for House of Commons Speaker.
MPs will vote later for a successor to Michael Martin.
Lady Hermon said she wanted to remain a "constituency MP". She is supporting Labour's Margaret Beckett.
Other local MPs are backing one of the numerous Conservative candidates, including John Bercow, Ann Widdecombe and Sir Patrick Cormack.
"It is a secret ballot and MPs are voting as individuals across party lines," said BBC NI political correspondent Stephen Walker.
"East Antrim MP Sammy Wilson is backing Ann Widdecombe, whilst Foyle MP Mark Durkan is supporting front-runner John Bercow."
"This election came about following Michael Martin's resignation and amidst the ongoing expenses row."
Lady Hermon said she was "flattered" by the request but said the role of Speaker would not suit her temperament, further to wanting to continue to focus on her constituency work.
MPs across all parties hope the new Speaker will be at the forefront of parliamentary reform.