NZ First's board will meet on Monday to vote on two options for forming the next government.
Kingmaker Winston Peters emerged from his party's caucus meeting on Friday morning to announce the country was a step closer to a decision being made.
Wearing a tie emblazoned with repeated TGIF lettering, shorthand for Thank God It's Friday, Mr Peters revealed members of the board would fly to Wellington on Sunday night and Monday for the meeting.
Talks could go into the night and a decision will be announced as soon as possible after the meeting, he added.
Mr Peters and his negotiating team held final meetings with National and Labour on Thursday, going late into the night.
"Any communication now will be between key officers and key operatives on either side so we can sort it out by phone call and text communication," he said.
A comprehensive dossier has been completed from the meetings with both sides.
They contain details of the concessions offered by National and Labour that will allow NZ First policies to be implemented by the next government.
There's nothing in them about ministerial positions - Mr Peters says that's something that can be worked out later.
Friday's caucus meeting is expected to conclude drafting documents that will be presented to the board meeting setting out what the party will get from the deals offered.
The Greens are essential to a centre-left government because Labour and NZ First don't have enough seats between them for a majority, but they've played no part in the negotiations.
Mr Peters insisted on negotiating only with National and Labour, leaving it up to Labour to deliver the Greens' support.