A significant storm is forecast to hit Southland this weekend, with the Met Service issuing a heavy snow watch for Southland, Fiordland, and south of a line between Queenstown, Alexandra and Mosgiel.

This is likely to bring heavy snowfalls above 300m and lighter falls (possibly to sea level) across much of the province.  

In Fiordland, snow is expected to fall down to 100 metres at times. Periods of heavy snow are possible above 300 metres where accumulations may approach warning criteria, especially south of Doubtful Sound. Snow is however expected to ease in the north from Saturday evening.

A brief period of snow is likely above 300 metres from Friday night on the Milford Road (SH94) through to the early hours of Saturday, and 1 to 3cm of snow may settle on the road. Another period of more significant snow is likely from 10am Saturday, then becoming confined south of Lake Gunn from 9pm and continues in the south into Sunday. 10 to 20cm is possible near the tunnel.

Snow is expected to fall down to 100 metres at times south of a line between Queenstown and Mosgiel, including Southland and Stewart Island. Periods of heavy snow are possible above 300 metres where accumulations may approach warning criteria.

South Roads have gritting and ploughing vehicles in place to respond across Southland's roading network.

Motorists are asked to restrict their travel if the forecasted weather eventuates.