The fast-moving system was expected to move quickly north over the South Island today and reach the lower North Island by late afternoon or early evening, MetService said.
Southerly winds were expected to be strong, rising to gales in eastern and coastal areas.
MetService issued a severe weather watch for Southland, Otago, Canterbury, Marlborough and Wellington last night.
The southerly winds could reach severe gales in Clutha and Otago during the morning, Banks Peninsula in the afternoon and in Wellington and the Kaikoura Coast by late afternoon or evening.
Up to 6cm of snow was expected on the Desert Rd tonight, with snow also expected on Lewis Pass, Arthurs Pass, Porters Pass, Lindis Pass and Milford Rd in the South Island.
The strong weather system should gradually ease in the eastern areas from Tuesday, MetService said.
Most of the country would be in for some settled weather by Wednesday and Thursday, with a few showers expected in the east coast of the North Island and southwest of the South Island.
