The Greens are calling for the "Skynet" copyright law to be scrapped after a study shows three-strikes laws are ineffective.

Green Party information and computer technology spokesman Gareth Hughes told Fairfax Media the Government should review its controversial "Skynet" Copyright (Infringing File-Sharing) Amendment Act.

A new paper from Australia's Monash University on copyright enforcement had found three-strike laws, or graduated responses, around the world were not working, he said.

The paper found similar copyright regimes in France, Taiwan, South Korea and Britain were ineffective at reducing online copyright infringement, Hughes said.

"Three-strikes laws are a failed approach and if it's not working it should be scrapped."

The paper found Kiwis were simply switching from Peer-to-Peer (P2P) file-sharing sites to other methods such as cyber-lockers to obtain content. The law was hardly acting as an effective deterrent to reduce online copyright infringement, he said.

The paper's author, law lecturer Rebecca Giblin, said there was little to no evidence that graduated responses were effective in terms of reducing copyright infringements, maximising authorised use of material, or promoting a variety of creative materials.

"The analysis casts into doubt the case for [the law's] future international rollout and suggests that existing schemes should be reconsidered," the paper said said.

Hughes said New Zealand's law was of "dubious effectiveness".

With only 13 cases brought in front of the Copyright Tribunal, New Zealand should terminate the law and focus on more effective solutions, he said.

The Government had missed an opportunity to test the effectiveness of the Skynet law by announcing the delay of its anticipated copyright review, Hughes said.

The Government announced in July it had put a review of copyright laws on hold as it tried to sew up the Trans-Pacific Partnership trade deal.

A review of the controversial legislation, passed in 2008, had been promised within five years.

In an undated Cabinet paper, published in July by the Ministry of Business, Innovation and Employment (MBIE), Commerce Minister Craig Foss noted "significant public demand" for a review.

However, he said it would be "impractical" to go ahead before the TPP deal was concluded "and the outcome made public".

Hughes said the Government should reconsider starting the copyright review given similar reviews or changes in Australia, Canada and Britain.

The most effective way to reduce online copyright infringement was to support online legal options to access copyright, he said.

"More Government attention in this area would do more to support Kiwi artists than the ineffectual Skynet law."

The number of "Skynet" rulings issued by the Copyright Tribunal hit double figures in July.

So far, 17 Skynet rulings have been issued by the Copyright Tribunal, a tribunal spokesperson said.

Recorded Music NZ, formerly the Recording Industry Association of New Zealand, represents record labels and lays complaints and sends infringement notices under the Skynet law.

Recorded Music general counsel and head of government affairs Kristin Bowman said the legislation was working.

However, the cost of sending infringement notices to infringers was prohibitive and needed to be lowered, she said.

Recorded Music had sent thousands of infringement notices since the law came into effect, she added.

In contrast with the Monash University study, Bowman said there had been a drop in P2P infringing and in overall piracy.

"We consider a contributor is also the amazing array of legal online music options now available - some of which are free."