WELLINGTON, Aug. 28  -- The New Zealand government was under renewed pressure Thursday to explain how much communications metadata it was sharing with its "Five Eyes" spying partners after new revelations from U.S. whistleblower Edward Snowden.

The opposition Green Party said the newly released documents from the U.S. National Security Agency (NSA) detailed a search engine, known as ICREACH, that contained more than 850 billion records of metadata on phone calls, mobile phone locations and e- mails.

The documents suggested the data was then shared among the Five Eyes partners: New Zealand, Australia, the United Kingdom, the United States and Canada.

A document from 2008 also stated that New Zealand's Government Communications Security Bureau (GCSB) electronic spy agency had agreed that the metadata it collected might be shared with the U.S. intelligence community, according to the Green Party.

"Once again, we're seeing evidence that directly links New Zealand spies to a global mass surveillance network," Green Party co-leader Russel Norman said in a statement.

"Changes made to the GCSB's powers last year mean they can now spy on New Zealanders and have the ability to access our communications via our telecommunication providers," said Norman.

"This new evidence puts the GCSB at the heart of the mass surveillance network and contradicts what Prime Minister John Key has been claiming all along -- that New Zealand doesn't supply information to outside organizations."

Key, who has repeatedly denied there was mass surveillance of New Zealanders, told Radio New Zealand Thursday that the GCSB operated within the law and that New Zealanders' data was safe.