There were significant delays on State Highway 1 north of Wellington due to heavy holiday traffic.
NZTA said traffic was congested for those heading north on SH1 between Peka Peka and Ōtaki.
Traffic was heavy for those heading north between Plimmerton and Paekākāriki.
Both areas had now eased of traffic and just southbound through Ōtaki remained heavily congested, NZTA said.
UPDATE 5:30PM— NZTA Wellington (@NZTAWgtn) December 27, 2018
Congestion from Peka Peka to Ōtaki has EASED significantly. Southbound through Ōtaki remains HEAVY. ^EL
The Transport Agency warned motorists to expect significant delays and to plan journeys ahead.
Earlier this afternoon, NZTA's traffic cameras showed SH1 northbound toward Pukerua Bay also appeared to be heavily congested.
SH1 PLIMMERTON TO PAEKĀKĀRIKI, NORTHBOUND - HOLIDAY CONGESTION - 12:40PM— NZTA Wellington (@NZTAWgtn) December 26, 2018
Traffic is HEAVY heading north between Plimmerton and Paekākāriki. Please expect #delays. Further north, traffic remains congested from Peka Peka to Ōtaki. Thank you for your patience and drive safely! ^EL pic.twitter.com/fNn14BKPiS
The Transport Agency says traffic today has been one of the busiest days so far this holiday season.
Its transport systems manager, Mark Owen, said there had been a lot of traffic in Wellington and Auckland.
He said holidaymakers were experiencing delays up to a hour earlier this afternoon.
But Mr Owen said traffic should now be easing.
There was also slow traffic heading north on SH1 out of Auckland due to planned roadworks, he said.
Popular holiday roads south of Puhoi and Wellsford were also congested, he said.
Meanwhile, State Highway 4 Raetihi to Whanganui has reopened with a stop-go operation in place between Kakatahia and Te Hue Road intersection.
The road was shut from Christmas Day due to multiple slips in the area, after bad weather battered the North Island earlier this week.
In the South Island, State Highway 8 completely reopened last night after being shut earlier in the day due to a truck on fire.
The closure was through Pukaki between State Highway 80 and Hayman Road, but it reopened to one lane after about 30 firefighters were called to the scene.