Unionist Don Pryde says he will be seeking selection as the Labour Party's Dunedin South candidate, opening up a contest with David Benson-Pope.
Mr Pryde is the national president of the Engineering, Printing and Manufacturing Union (EPMU).
He is a longstanding member of the Labour Party and the party's Dunedin South local electorate committee.
Mr Pryde, a father of three, said today he felt it was time to step up to a more public representative role.
EPMU secretary Andrew Little said Mr Pryde had the union's full support.
There had been speculation Labour Party official Clare Curran would throw her hat in the ring, but wanted to avoid a messy fight with Mr Benson-Pope for the candidate selection.
Ms Curran could not immediately be contacted today to see if she will stand now the contest has been opened up.
Despite speculation he would step down, Mr Benson-Pope recently filed his nomination for the Dunedin South electorate with the party.
Prime Minister Helen Clark has avoided endorsing Mr Benson-Pope, who was forced to resign from Cabinet over the Madeleine Setchell affair.
Ms Setchell lost her Environment Ministry communications job after the fact that her partner, Kevin Taylor, was the National Party's chief press secretary became an issue.
Miss Clark has not commented on the candidate selection process.
The Little Things, Dilbert, Tom Scott and others
Test your mind with our puzzles
What do the stars have in store for you today?
Dig into New Zealand's archives
Decide what news you want to receive when it suits you
Keep up with the latest news by making us your homepage