The United Future Party has announced it will not stand a candidate in the Mana by-election.
The United Future leader, and its sole MP, Peter Dunne, says the by-election would place a strain on the party's resources, which it would prefer to hold for next year's general election.
He says United Future's focus in electorates such as Mana is the party vote, and there is little to be gained by MMP parties becoming involved in the by-election.
Mr Dunne says the party's board has decided not to contest the by-election, although it will stand a candidate in Mana at the 2011 general election.
The Mana by-election to replace the retiring Labour MP, Luamanuvao Winnie Laban, will be held on 20 November.