National MP Stuart Smith says he was making an "educated guess" when he apparently let slip when State Highway 1 north of Kaikōura would be re-opened.

Photo: RNZ / Rebekah Parsons-King

Speaking at a candidates meeting in Blenheim yesterday morning, the MP for Kaikōura said the road would be open again by 15 December.

Photo: Supplied / National Party

But he told Morning Report today that while there was "huge progress" being made on the road, he could not confirm an exact date.

"It's an educated guess, it's 10 days before Christmas, in the middle of December, and everything is on track as we get closer to it."

The NZ Transport Agency is planning to have the work completed by Christmas, but would neither confirm nor deny the December date.

Mr Smith said it was "probably a mistake" to give a definite date at yesterday's meeting as "people are drawing all sorts of conclusions from it".

He said the road was still four months away from being opened, and there could be more extreme weather or other events that could cause delay, and an official opening date would not be announced until closer to the time.

NZTA said it planned to give more information by the end of September to allow holiday-makers to plan ahead.