A potential snow storm is making it's way across parts of the country next week

MetService is forecasting a low pressure system forming in the Tasman Sea.

Metereologist Lewis Serris says it's expected to collide with a cold blast moving in from the South.

He says that allows for potential snow falling in parts of the South Island that haven't seen any so far this year

Serris says there's the risk of widespread snow down to 500 metres in central and southern parts on Tuesday - and lingering risks into Wednesday as well.

He says inland areas could possibly see even lower snowfall on Monday and Tuesday.