Cook Strait ferries have cancelled this weekend due to forecast six-metre swells.

Interislander has canned all passenger sailings for Saturday due to the conditions.

“All passengers are being moved to alternative sailings,” it said on its website.

Bluebridge has also cancelled all Saturday sailings, and one in the early hours of Sunday morning.

The MetService says waves could reach swells of six metres on Saturday, with a warning lasting to Sunday morning.

A fresh surge of winter weather was expected to descend on the South Island on Friday, bringing snow, sub-zero temperatures and the risk of travel disruption.