The New Zealand First has held negotiations with both over the past week, but has kept the country guessing over which way it was leaning.
The political uncertainty has pushed the New Zealand dollar down 2.9 percent against the US dollar since the vote.
After the 23 September election the National party was left with 56 seats and Labour 46 - both short of the 61 needed to form a government in the 120-seat parliament.
So far, there had been no talks of ministerial positions and the party was still working through policy.
Mr Peters had originally set yesterday as a deadline for a decision, before pushing that date back due to the "logistics" of getting his board together for a meeting.
The NZ First leader's insistence that the identities of the board members remain a secret has been criticised by political commentators, who say New Zealanders have a right to know which group of people will be charged with making the country's biggest political decision in almost a decade.
Plusieurs blessés dans une fusillade, la piste terroriste écartée — Suède
Les forces de l'ordre avaient dans un premier temps fait savoir que quatre individus, tous des hommes, avaient été blessés. La police est rapidement arrivée sur place.
He expected constant communication between his party and National and Labour through phone and text, but there were no more face-to-face meetings planned.
Winston Peters says the decision will be announced as soon as possible after the board has met. "This is the scenario that Peters is asking the public to accept without question - in fact, Peters has slapped down journalists" questions about NZ First board members as "stupid and mindless'".
"They give up their valuable spare time to take part in board meetings and attend to other matters, and we are grateful for that".
They contain details of the concessions offered by National and Labour that will allow NZ First policies to be implemented by the next government. The New Zealand dollar was last 0.07 percent lower at $0.7125.
Time is of the essence, Mr Peters said.
A National/NZ First government would have 65 seats, while a Labour/Greens/NZ First government would have 63 seats.
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