The Prime Minister has once again assured New Zealanders they will not be subject to widespread spying, now that the GCSB bill has passed into law.
John Key told Morning Report the law was never going to win the hearts and minds of all New Zealanders.
He said the legislation is designed to protect New Zealand citizens and wholesale spying will not be allowed.
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The Government Communications Security Bureau and Related Legislation Amendment Bill was passed by 61 votes to 59 at 7.45pm on Wednesday.
Labour and the Green Party say they would repeal the law if they are in a position to do so, after the 2014 general election.
A report into the GCSB earlier this year called into question the legality of 56 operations involving 88 individuals since 2003.
This resulted in the suspension of any domestic spying while the law was changed to clarify the bureau's activities.
Earlier, Mr Key said the GCSB will have three functions under the bill: these include assisting the SIS, the police and Defence in warranted interceptions of New Zealanders.
The GCSB was formerly able to collect only foreign intelligence.
In Parliament on Wednesday, Mr Key said that since he became prime minister 4½ years ago he had been frequently briefed by the intelligence agencies on issues which deeply concerned him.
"If I could reveal them, they would cut dead some of those who oppose this bill," he said.
"I can't, all I can do is assure New Zealanders the GCSB is essential to our national security."