While there had been no reports of slips or damage on other highway,s strong winds had made driving challenging.
Mr Oldfield said the agency had set up a specialised "Winter Journeys" website:
nzta.govt.nz/winter-journeys - and urged people planning trips to check it out.
He said the main points revolved around planning the journey, considering if they really had to travel if the weather was turning severe, check out road conditions and forecasts and think about the best route for the planned destination.
"Choose safety over convenience."
Weatherwatch forecasters said New Zealand would be back to windy and wet weather on Thursday with rain right along most of the nation's western coastline of both islands and strong to gale force westerlies blowing for many regions, although temperatures would be relatively mild.
However, weather patterns going into the last weekend of July shows the country is likely to be exposed to a nationwide polar blast for the first time this winter.
"But we still need a couple more days to lock it in - these air pressure systems are definitely moving around pretty quickly at the moment so things might change a bit."