WELLINGTON, March 26 -- New Zealand's watchdog over the country's spy agencies launched an investigation Thursday into claims that the electronic surveillance agency illegally spied on New Zealanders across the South Pacific.

The probe follows a series of revelations by the New Zealand Herald newspaper and the U.S. news site The Intercept that the Government Communications Security Bureau (GCSB) conducted "full- take" surveillance on Pacific nations.

This allegedly included targeted operations to spy on the e- mails and other communications of politicians, but it might also have illegally netted the communications of New Zealanders living and working in Pacific nations.

The Inspector General of Intelligence and Security Cheryl Gwyn said she would start an inquiry into complaints over alleged interception of communications of New Zealanders by the GCSB.

"The complaints follow recent public allegations about GCSB activities. The complaints, and these public allegations, raise wider questions regarding the collection, retention and sharing of communications data," Gwyn said in a statement.

There was also a clear need to provide as much factual information to the complainants, and to the wider public, as possible, she said.

For that reason, she had decided to also bring forward and expand the relevant parts of an ongoing review and audit of GCSB procedures and compliance systems, she said.

The opposition Green Party, which made one of the complaints to Gwyn's office about the spying, welcomed the inquiry, saying the allegations were very serious.

"The documents that were released show systemic spying on New Zealanders who were working or traveling in the South Pacific," Green Party co-leader Russel Norman said in a statement.

"There have been over 1.6 million visits by New Zealanders to the Pacific since 2009; all of those people deserve to know whether they were spied on."

Norman, also called on Prime Minister John Key, who has ultimate responsibility for the spy agencies to "come clean on what the activities of the GCSB were and how much he knew."

The revelations were based on materials supplied by U.S. National Security Agency whistleblower Edward Snowden and showed New Zealand spy agencies operated surveillance on friendly countries in the Pacific and Asia.

It was also revealed the GCSB had monitored e-mail and Internet traffic about international diplomats vying for the job of director general of the World Trade Organization during Trade Minister Tim Groser's failed campaign for the post.