MetService has issued a snowfall warning for Desert Road - State Highway 1.

Snow is expected to affect the road early Tuesday morning, says a MetService spokesperson.

One to two centimetres of snow is expected to settle above about 800 metres.

The warning is valid for four hours from 4am to 8am Tuesday October 3.

A trough is bringing severe gales to parts of southern and central New Zealand today, with brief heavy rain for the west of the South Island.

Warnings and Watches for severe gales and heavy rain are in force.