Former taoiseach Enda Kenny is expected to confirm within weeks he will not contest the next general election.
Mr Kenny, who stood aside as taoiseach earlier this year, has made no comment to date on his future intentions.
A meeting has been called of the local constituency branch in Castlebar this week but Mr Kenny is unable to attend due to a previous commitment. However, it is understood he will inform his constituency colleagues of his decision not to stand again at a meeting of the branch next month.
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The former taoiseach will also confirm none of his family will stand in his place. His daughter Aoibheann had been speculated on previously.
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Mr Kenny has been a TD since 1975 and served as leader of Fine Gael for 14 years.
According to the Mayo News, the party is already assessing possible replacements for Mr Kenny and is considering approaching Mayo footballer Andy Moran. It says no official approach has been made to Mr Moran by the party.
Minister for Rural Affairs Michael Ring and Senator Michelle Mulherin will both stand for election. It is not known if Senator Paddy Burke or Senator John O'Mahony will put their names forward.
Mr O'Mahony stood in Galway West constituency in the 2016 election but was unsuccessful. He may be asked to stand in Mr Kenny' s place in Mayo.
Former minister for finance Michael Noonan has confirmed he will not stand for re-election.
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