Former National Security Agency systems analyst turned leaker Edward Snowden said Monday that the NSA is collecting mass surveillance data on New Zealanders through its XKeyscore program and has set up a facility in the South Pacific nation's largest city to tap into vast amounts of data.

Snowden talked via video link from Russia to hundreds of people at Auckland's Town Hall.

Shortly before he spoke, New Zealand Prime Minister John Key issued a statement saying New Zealand's spy agency, the Government Communications Security Bureau, or GCSB, has never undertaken mass surveillance of its own people. Key said he declassified previously secret documents that proved his point.

"Regarding XKeyscore, we don't discuss the specific programs the GCSB may or may not use," Key said. "But the GCSB does not collect mass metadata on New Zealanders, therefore it is clearly not contributing such data to anything or anyone."

Snowden, however, said Key was carefully parsing his words, and that New Zealand agencies do collect information for the NSA and then get access to it.

"There are actually NSA facilities in New Zealand that the GCSB is aware of and that means the prime minister is aware of," Snowden said. "And one of them is in Auckland."

He said Key was avoiding the main issue by not talking about XKeyscore.

"To this day, he's said I won't talk about this. I won't talk about this because it's related to foreign intelligence," Snowden said. "But is it related to foreign intelligence if it's collecting the communications of every man, woman and child in the country of New Zealand?"

The event in Auckland was organized by indicted Internet entrepreneur Kim Dotcom. It also featured American journalist Glenn Greenwald and WikiLeaks founder Julian Assange, who spoke via video link from London.

Greenwald produced NSA slides that he said showed the GCSB had taken steps to engage in mass surveillance through a program called Project Speargun.

But Key said the program was rejected, and instead an alternative program that organizations needed to opt into was adopted.

"Put simply, it never happened," Key said.

The Town Hall event came five days before New Zealand's general election. Dotcom, who is fighting U.S. attempts to extradite him on racketeering charges over his now-shuttered file-sharing site Megaupload, has been campaigning in the election for a political party he is funding and has said he hopes to oust Key.

Dotcom earlier said that he would produce proof that Key had misled the public about his case, but he did not mention anything about that at the event.