Labour MPs will gather next week to plot strategy for an election contest dramatically changed by John Key's resignation.
The party's MPs will return after a summer holiday for a New Year caucus in Martinborough on Monday and Tuesday - aware a successful campaign could put them in power later this year.
Prime Minister Bill English, currently in Europe, is yet to call a date for the election.
Key's shock resignation has changed the "dynamic" of the election contest, Labour leader Andrew Little said.
"There is a different personality leading the National Party, so that will make a difference. But, equally, we don't take anything for granted. No one is heaving a big sigh of relief saying, 'that's it, we've got it in the bag'. We know we have work ahead of us.
"We are constantly looking at what we do, what we need to be doing better, and what we need to change.