Fog, slips and crowds of Boxing Day shoppers have caused hold-ups in some parts of the country today.
A section of State Highway 1 through Auckland became congested about midday due to shoppers flocking to sales at Sylvia Park mall.
At the bottom of the North Island slips closed State Highway 4 between Whanganui and Reitihi, and there was heavy traffic on SH1 north of Otaki.
A Transport Agency spokesperson said traffic was expected to ease over the next few days.
The spokesperson said drivers should plan to travel in the early morning or evening if they want to avoid delays.
Beside State Highway 8 in Canterbury's Mackenzie District, fire crews have contained a number of grassfires.
The fires started after a truck caught fire east of the intersection of State Highways 8 and 80.
The road was closed to traffic and about 30 firefighters were called to the scene.
Fire Service spokesperson Andrew Norris said no-one had been injured, and some of the fires have been put out since they were alerted about 3.15pm.
"We're unable to confirm at this stage how many fires we have but we believe there's somewhere around the vicinity of 10, ranging in size from a couple of hundred of square metres to multiple hundreds of square metres," Mr Norris said.
Most of the fires have been put out and the road has reopened to one lane of traffic.
But motorists are advised to expect delays.
Meanwhile, flights around the country are back to schedule after disruptions this morning caused by fog at Wellington airport.
Some services were cancelled at Wellington Airport, and other services were delayed in Auckland, Christchurch, Dunedin and Queenstown.
Wellington Airport said operations were back up and running but some airlines would still be clearing a backlog of passengers.
Air New Zealand is advising passengers booked to travel later today to check the flight schedule.