Christmas could come and go before New Zealand gets a new government, with neither Christopher Luxon nor Chris Hipkins willing to promise a coalition deal before the festivities are over.

On Monday, both prospective prime ministers refused to put a deadline on coalition talks, raising the prospect of Christmas being swallowed up by political horse-trading.

Asked on RNZ's Morning Report about the timeframe, Luxon was non-committal.

"I'm hoping that we can get something put together before Christmas - would be ideal. But frankly, it'll take as long as it takes."

Luxon indicated formal negotiations would likely wait until the final vote count was released on 27 November, nearly three weeks after polling day.

"We'll probably need to wait for that to come back, and then you'll see negotiations commence," he said.

"That's why I'm asking New Zealanders first and foremost to think very intentionally about how they want to vote."

Hipkins was similarly reluctant to make promises, telling reporters at Parliament it would depend on what voters delivered.

"We've got to play the cards that the voters deal us. If you want a good, decisive outcome, vote for one. Vote Labour.

"Give us the strongest possible hand in those post-election discussions."

On Sunday, Hipkins said he would make it a priority to get a deal done before Christmas, but he could not guarantee it.

"It's one of the later elections that we've had in recent times, and that could, depending on the outcome, make it more challenging."

In 2023, it took National, ACT and New Zealand First 41 days after voting day and 21 days after the final count to sign their coalition agreements.

The same timetable this year would take us to 18 December - just one week before Christmas.

The 2017 negotiations were quicker, with NZ First leader Winston Peters announcing his decision to go with Labour 26 days after the election and 12 days after the final count. The agreements, however, were not formally signed for another five days.