Holidaymakers heading home to Auckland are being warned to expect traffic delays this afternoon and through to this evening.
And wild weather drenching much of the country is likely to cause delays for motorists returning home to other main centres, with slips, surface flooding and road closures.
The NZ Transport Agency said State Highway 1 Wellsford to Puhoi, southbound, was tipped to be busy from 10am to 7pm for southbound traffic.
"Road users are advised to expect delays and consider using SH16 if heading north,'' the NZTA said.
Authorities were also warning about expected traffic congestion on State Highway 1, Takanini, between 10.30am and 8pm.
Heavy rain this afternoon has made for difficult driving conditions throughout the day.
Emergency services are at a crash on the north-western motorway, near the Huruhuru Rd over-bridge in Massey.
NZTA said just before 5pm the crash was blocked the left east-bound lane.
It is not yet known whether anyone has been injured, but delays are expected in the area.
Congestion is building as a result of the crash and queues are backing up towards Royal Rd.
South of Auckland, on the Southern Motorway near the Ramarama exit, a multiple car crash just before 1.30pm blocked the right northbound lanes.
Motorists were asked to pass with care as authorities worked to clear the area. The road was cleared shortly afterwards, but delays continued for some time.
There had earlier been a fuel spillage on the Auckland southern motorway near Ramarama - between SH1 and SH2 - just after lunchtime, which also blocked some parts of the motorway and caused delays this afternoon.
In northern Waikato, emergency crews are at the scene of a crash near the Nikau Rd over bridge.
The accident happened about 3.15pm.
The NZTA said: "Please pass the scene with care and expect some delays.''
South of the country, a South Island Advisory showed State Highway 1 north and south of Kaikoura would be closed tonight from 6pm due to predicted poor weather.
Motorists in Otago and Southland areas were also warned about ice and black ice on various roads and highways.
Otago:
• SH85 Alexandra to Kyeburn – Ice – Road users are advised to take extra care.
• SH6 Kingston to Frankton – Ice – Road users are advised to take extra care.
• SH8 Lindis Pass – Black Ice – Caution – Road users are advised to take extreme care.
• SH6 Queenstown to Cromwell – Ice – Road users are advised to take extra care.
• SH8 Omarama to Twizel – Black Ice – Road users are advised to take extra care.
Southland:
• SH96 Wreys Bush to Dunearn – Slippery Surface – There is a temporary speed limit of 50km/h – Road users are advised to take extra care.
• SH98 Dacre to Lorneville – Black Ice – Road users are advised to take extra care.
• SH94 Te Anau Downs to Gulliver River Bridge – Ice – Caution – Expect icy conditions this morning.
• SH94 Te Anau to Mossburn – Black Ice – Caution – Road users are advised to take extra care.
• SH96 Winton to Mataura – Black Ice – Road users are advised to take care.
NZTA has a list of the forecasted Queen's Birthday Holiday Hotspots 2018, based on traffic congestion and incidents in previous years.
Meanwhile, those planning to drive today were urged to check for real-time travel information via the journeys.nzta.govt.nz website or to call 0800 4 HIGHWAYS (0800 44 44 49) for information.
Motorists were also encouraged to keep up to date with weather updates.
The crash happened in Ōpārau near Ōtorohanga about 8.45pm on March 30.