Labour Party president Andrew Little says the party is well positioned to fight the Mana by-election, and could cope with a second campaign in Te Atatu if necessary.
Mana MP Luamanuvao Winnie Laban is retiring from politics to take up a job at Victoria University, which will trigger a by-election in the traditionally safe Labour seat, probably in November.
If Labour's embattled MP Chris Carter was also to leave Parliament, a by-election could be held in Te Atatu as well.
Mr Little says the party will be looking for a strong, new candidate with links to the electorate in Mana to replace Winnie Laban.
He says the party's fund-raising has been pretty steady, so it is set up for a by-election in either Mana or Te Atatu, or both.