UPDATE 1.45PM: State Highway 4 has reopened following an earlier crash.

All Central North Island state highways are now open, says Waka Kotahi Transport Agency.

"Motorists should continue to expect winter driving conditions and keep their speeds down, maintain a safe following distance and stay alert.

"People can also check the Waka Kotahi Facebook, Twitter and Journey Planner webpages for the latest weather and road conditions before setting out."

UPDATE 12.05PM: State Highway 1 has reopened between Waiouru and Rangipo (Desert Road).

Waka Kotahi Transport Agency says State Highway 47 has also reopened.

"However, State Highway 4 is now closed between Tohunga Junction and National Park due to a crash," says a spokesperson for the roading agency.

"Motorists should continue to expect winter driving conditions and keep their speeds down, maintain a safe following distance and stay alert."

People can also check the Waka Kotahi Facebook, Twitter and Journey Planner webpages for the latest weather and road conditions before setting out.

UPDATE 11.04AM: State Highway 49 is now open.

Waka Kotahi Transport Agency says SH1 has also reopened between Taihape and Waiouru, but remains closed between Waiouru and Rangipo (Desert Road).

Police are warning people to check travel conditions before they set off on the journey. Photo: Bay of Plenty and Taupo Police Facebook.

EARLIER:

Motorists are being encouraged to delay their travel where possible as state highways throughout the Central North Island remain closed this morning due to snow and ice.

A cold front has swept across New Zealand in the past 24 hours, leaving motorists stranded, closing schools and bringing a heavy dusting of snow on ski fields.

Waka Kotahi NZ Transport Agency advises the following roads are currently closed:

-State Highway 1 Taihape to Rangipo (including Desert Rd)

-State Highway 4 Tohunga Junction (Ohakune) to National Park

-State Highway 41 Manunui to Kuratau

-State Highway 47 Rangipo to National Park

-State Highway 49 Waiouru to Tohunga Junction (Ohakune)

-Napier-Taihape Rd

State Highway 5 Napier-Taupo is open, says a spokesperson for the roading agency,

'Motorists are encouraged to delay their travel where possible. Detours are via State Highway 3 New Plymouth or SH5 Napier and will add significant time to a journey.

'Those who are travelling should expect winter driving conditions and keep their speeds down, maintain a safe following distance and stay alert.”

Bay of Plenty and Taupo Police are also asking people to plan their journeys before hitting the road.

'Don't rush. These conditions look beautiful in the photo above, but can be treacherous.”

Plan ahead for a safe, enjoyable journey. Keep up to date with:

• Traffic updates: journeys.nzta.govt.nz/traffic
• Facebook: facebook.com/nztacni
• Twitter: twitter.com/WakaKotahiCNI
• Journey planner: journeys.nzta.govt.nz
• Phone: 0800 4 HIGHWAYS (0800 44 44 49)