A significant low-pressure system will move slowly over New Zealand from Friday through Sunday, with a sustained period of southeasterly airflow over Canterbury from around midday Saturday through early Monday morning.

Blueskies weather is warning farmers that snowfalls from this system look likely to be confined to higher levels, but accumulations at those levels could be substantial.

Between Saturday afternoon and Monday morning expect 30cm to accumulate above 800m and 50cm above 1000m.

In North Canterbury accumulations above 1000m may reach 70-80cm.

 For travellers: Alpine passes could experience heavy rain and sleet at times, but significant snowfalls seem unlikely.

 Higher hills and ranges in Otago will see some snow on Friday and Saturday.