Mr Ahern was a member of Fianna Fáil from the late 1960s until 2012.
He left the party shortly before it was due to hold a meeting to consider expelling him over the findings of the Mahon Tribunal into planning matters.
However, at a meeting on Tuesday night, a motion was passed inviting Mr Ahern to become a member again.
The 65-year-old Dubliner was the most successful Irish politician of his generation, having been elected taoiseach three times in successive general elections from 1997 to 2008.
In 2012, the Mahon Tribunal found that he had failed to truthfully account for lodgements of 165,000 Irish punts into accounts associated with him, but the report stopped short of accusing him of corruption.
Fianna Fáil is no longer in government and is now the Republic of Ireland's largest opposition party.
The vote to invite Mr Ahern to become a member again was taken at a meeting in his former Dublin Central constituency branch.
Fianna Fáil's national executive is now expected to write to Mr Ahern informing him of Tuesday night's motion.
The former taoiseach, who has raised his profile in recent months, was unavailable for comment on whether he intended to rejoin his former party.
Former Taoiseach (Irish Prime Minister) Bertie Ahern may be about to rejoin the party he resigned from after a report into alleged planning corruption.