One of New Zealand's largest internet providers says Sky Television has issued a demand that it block access to websites hosting pirated material.

Vocus New Zealand, which owns the Orcon and Slingshot internet brands, said Sky issued the demand to its business and to Spark, Vodafone and 2degrees.

Vocus consumer general manager Taryn Hamilton said the demand was "absolutely unprecedented" in New Zealand.

"It something you would expect in North Korea, not in New Zealand".

"It isn't our job to police the internet and it sure as hell isn't Sky's either. All sites should be equal and open," he said.

Sky has been contacted for comment.