MetService is forecasting a cold southerly outbreak, bringing cold air and rain this week

The rain's expected to fall as snow on mountains, and down to as low as 400 to 700 metres above sea level over parts of the South Island.

Meteorologist Mmathapelo Makgabutlane says the first heavy snow watch has been issued for the Queenstown-Lakes and Central Otago Districts.

She says it might not quite reaching lake level in Queenstown, but snow could reach areas that are a little bit more elevated.