Digital rights and hacking collective Anonymous says it will launch an operation, "Kiwi Freedom", in New Zealand over the next week in protest at the passage of the Government Communications Security Bureau Act.

The threat was contained in a seven-minute video posted on YouTube that bore the hallmarks of a genuine message from Anonymous activists.

Protest tactics used by Anonymous in the past have included "denial of service" attacks that use networks of malware-infected computers to bombard and block access to government websites, and the hacking and release of sensitive government information.

In the video, "Anonymous" said New Zealand had earned the "moral high ground" in the past because of its anti-nuclear stance, but the group was disappointed with the passage of the GCSB Act.

Anonymous also drew attention to a Fairfax report that said the United States Department of Defense had an interest in acquiring a pair of optical-fibres on the US-Australia and American Samoan legs of a new fibre-optic cable network being proposed by New Zealand-registered company Hawaiki, to link its military bases in American Samoa and forthcoming Marine Air Ground Task Force base in Darwin.

The US Defense Department and Hawaiki have declined to confirm or comment on the original Fairfax report. Anonymous said it feared the link would allow the greater transfer of data between the United States' National Security Agency, the GCSB and "other para-military regimes".

Anonymous said it was clear New Zealand was "more involved in mass surveillance than anyone thought" and it had decided to broaden the scope of its operations in New Zealand "to remind your government they do not control their citizens .. and are not in charge of our rights to freedoms".