Opposition parties say they see no need to extend the powers of the Security Intelligence Service beyond its current capabilities.
The Prime Minister has revealed he was considering changes to the SIS legislation, which he described as outdated and containing deficiencies.
The Act governing the GCSB was recently overhauled, following controversy over mass surveillance and some of its operations.
SIS director Rebecca Kitteridge has suggested the law for that agency should also be changed, because now it focuses almost solely on the process the SIS must follow to get warrants to intercept people's communications.
The Labour Party said a strong case would have to be made for any extension to its existing powers.
Labour leader Andrew Little said he would be very wary about any extension of powers, and he did not buy the argument that changes to technology in past decades meant the agency should have more powers.
The Greens said they outright opposed any move to increase the agency's powers, but said it should be forced to be more transparent.