Low-lying fog near Woodville and Pahiatua in the southeast of the North Island is making driving difficult.
Police have issued a warning to motorists this evening, saying visibility is an issue on roads in these areas.
Drivers should drive to the conditions and put their headlights on, police say.
The poor driving conditions may make it difficult to see cyclists, pedestrians and slower traffic, including trucks and vehicles towing trailers, boats or caravans during the holiday weekend.
Monday is the Queen's Birthday public holiday in New Zealand.
Six people have died on roads so far this weekend, one more than last year, despite warnings from safety agencies.