Roads in the central North Island closed due to snow falling overnight are now open, but motorists are being warned to drive carefully with winter officially starting in two days.

The re-opened roads include SH47, between National Park and Tongariro Forest, SH46, between Rangipo and SH47, SH4, between Erua and Mananui, SH1, between Rangipo and Waiouru, SH2 near the Rimutaka Hill and SH50, between Breakwater Road and Port of Napier.

The Desert Road is now open after it was closed due to snow.

Central District road policing manager Inspector Dave White says the frosty mornings and wet weather are signs that winter has well and truly arrived and this means that driving to the conditions is vital.

'The season provides some challenging driving conditions including snow and black ice on roads.

'We have already had a number of crashes in the district this morning from black ice so I want to remind drivers that they need to be alert and adapt their driving.”

The MetService says frigid temperatures are expected to set in, despite heavy snow easing in central and southern parts.

Communications meteorologist John Law says cold air spreading across the country from Antarctica is going to prompt a lot of people reaching for extra lawyers this week.

'The combination of strong winds and low temperatures is going to make it feel bitterly cold.”