NZTA is warning South Island motorists to be careful this weekend, with wild weather forecast

Metservice has issued heavy rain watches in some central parts and snow as low as 500 metres across Canterbury high country.

Affected roads include the alpine passes, inland state highways in Canterbury and the Mackenzie Basin, the Kaikoura coast and State Highway 75 on Banks Peninsula.

System manager Mark Pinner if conditions are bad enough, road closures or speed reductions could be put in place.