Holiday traffic in Auckland is snarling up after a crash on the Auckland Harbour bridge heading north.
The NZ Transport Agency said the crash was partially blocked the right lane on the northbound clip-on on the bridge, but was now clear.
However, motorists can expect delays from Wellington St.
A person crossing the Harbour Bridge told the Herald he had seen multiple crashes on SH1 near the bridge, and in both directions.
"One of them likely have caused injury of a motorcycle driver, police and ambulance are at scene, providing emergency treatment."
Photos show a injured person being helped by several others near the crest of the bridge.
NZTA warned motorists to take extra care.
Glenfield man Kahn Miao witnessed the aftermath of the crash.
He said it appeared four vehicles were involved, one of which was the motorcycle.
He saw an injured person on the ground near an upright motorcycle, and said that person was being tended by passersby and emergency services' staff.
Miao had travelling south to Auckland International Airport to catch a flight to Australia when he came across the crash.
"I was a little bit worried because it was heavy congestion."
Despite the delay he reached the airport in time to make his flight, with his 70 minute journey about half an hour longer than usual.
Traffic appears to be clear in other parts of the country, with fixed cameras showing free-flowing traffic in much of Hamilton, Wellington, Christchurch and Dunedin.
However, NZTA Wellington is keeping travellers updated on increasing holiday traffic congestion via its Twitter account.
Travel times at 4.35pm in Wellington are just over an hour to Paekakariki and 86 minutes to Waikanae.
It will take 18 minutes to get to the airport, NZTA Wellington tweeted.
A crash which seriously injured one person and closed part of State Highway 2 north of Masterton has now been cleared.
"The crash is now clear and the road is fully open. Please continue to #DriveSafe", NZTA Wellington tweeted.
Traffic is now easing on the southern routes out of Christchurch, NZTA Canterbury/West Coast has tweeted just before 5.45pm.
Earlier, the worst delays in Auckland are for those heading south of the city, with queues along much of the Southern Motorway, especially between Newmarket and Greenlane and Mt Wellington and Takanini.
Manukau is especially hard hit, with eastbound State Highway 20 traffic merging onto SH1 just after the Redoubt Rd exit.
Northbound traffic is moving more freely, with congestion only between Mt Wellington and Greenlane and a fairly clear run north of the Harbour Bridge.
There is congestion at the Northern Gateway tunnels.
Other Auckland motorways remain mostly clear - for now.
Both SH16 and SH18 are free-flowing, but there are some queues for eastbound SH20 traffic at Lambie Dr and westbound at Great South Rd.
The only area outside of Auckland experiencing heavy traffic so far is westbound traffic on SH1 at Cobham Dr West in Hamilton, where queues were beginning to form just before 3pm.
Transport for Christchurch posted online this afternoon that holiday traffic was expected to start building on SH1, north and south of the city, soon.
"Currently traffic is predominantly free flowing around this city. Motorists can plan their journey by using the NZ Transport Agency Labour Weekend Holiday Hotspots, take extra care and allow plenty of time to get to their destination."
WeatherWatch head analyst Philip Duncan said those on the road tonight and tomorrow morning can expect mostly dry conditions around the country.
Only the east coast of the North Island, between Wairarapa and Gisborne, would be affected by poor weather, with downpours this afternoon and evening, Duncan said.
"Some of those could be a little intense but as long as people are keeping their distance, it's probably not much of an issue."
Showers in North Canterbury and eastern Marlborough are clearing this afternoon.
And a cold overnight change could deliver frosts to some inland parts of Canterbury, Otago and Southland.
Overall, much of the country could expect a great Labour weekend, with most enjoying at least two good weather days.
"This is probably one of the best long weekends we've had in five years. We don't have storms, we don't have winds and we don't have ice."
However, motorists can still expect some headaches - courtesy of their fellow travellers.
Ahead of the long weekend, the NZ Transport Agency released a list of holiday weekend traffic congestion hotspots.
It said State Highway 2 at Maramarua travelling east will be heavy today from 11am-8pm, and on Saturday from 9am to 10.30am. The worst traffic heading west through the same spot on Monday will be from 11.30am to 3pm.
SH1 at Taupiri and Karapiro will be heavy from 1.30 this afternoon onwards, and again from 11.30 on Monday morning.
In the Bay of Plenty SH29 at Kaimai and SH2 between Paeroa and Tauranga will be heavy for a short time this evening, from 5.30 to 6.30.
In the central North Island SH1between Waiouru and Taihape will be heaviest for northbound traffic from 12.30pm to 6.30pm today, while SH5 at Te Pohue north of Napier will be heavy west and eastbound on Monday afternoon.
North of Wellington, SH1 at Waikanae will be heaviest northbound from noon today through to 8pm, and again tomorrow from 10am to 5pm.
SH2 at Rimutaka Hill will be heaviest heading northbound for an hour from 11am on Saturday, and again southbound on Monday from 2pm to 5.30pm.
Waipara north of Christchurch will be heavy heading north on SH1 from 4.30 to 6.30 this evening, and again southbound from 1pm to 6pm on Monday.
SH1 will also be heavy south of the garden city between Ashburton and Christchurch heading south from 1.30pm to 5.30pm today, and again tomorrow morning from 9 to 10.