Mr Dunne said: "If we're collecting all this stuff holus bolus, the first question is why. If the answer is 'because that's what Five Eyes says we should do and we simply hand it over to somebody else' ... that should be a proposition the (Intelligence and Security) committee might want to give some consideration to, whether or not that's what we want."
He said if it was the case information from the Pacific was then provided to the US after New Zealand had taken what it needed, then it would "raise some pretty serious questions about the function of our intelligence agency".
The Five Eyes alliance comprises Australia, Canada, New Zealand, the United Kingdom and United States. Documents obtained by Snowden while contracting to the US National Security Agency have shown the countries collaborate to build a global surveillance network.
Mr Dunne's role in the inquiry is critical - its existence was a concession wrought from the Government in return for his critical vote to pass legislation in 2013 seen by many as broadening the powers of New Zealand's intelligence agencies.
The review is to be held before the end of June.
The Government has yet to develop any details with Justice Minister Amy Adams due to set terms of reference.
Mr Dunne said he had not been consulted but had expected he would be - and would have thought work would be more advanced.
"I'm a wee bit concerned that they are dragging it out to the last minute to commence it. I've made some noise from the sidelines but I don't think my views are being heard."
He said the review - which he expected to be lengthy and rigorous - would be a "big test of the credibility" of the ISC.
"I would like to think as much of its business as possible will be done in public. I think if it starts to go behind closed doors then a credibility issue will arise."
The Prime Minister, asked about the review this week, said it "starts in the middle of 2015".
Mr Dunne also said comments on radio yesterday by Sir Bruce Ferguson, a former head of the GCSB, had raised concern. The former Chief of Air Force-turned-spy boss said "mass collection" occurred and included New Zealanders' information.
A spokeswoman said Mr Key would not talk about Sir Bruce's interview: "Conclusions that have been drawn from the interview do not accurately reflect the GCSB's activities."
Dunne's role
What's happened?
Peter Dunne used his critical vote to support new spy laws in 2013 in return for an inquiry into the intelligence agencies which, by law, must be held before the end of June this year.
What's the latest?
There isn't one. Mr Dunne thinks it should be more advanced but Justice Minister Amy Adams is waiting on the Intelligence and Security Committee - made up of Labour and National - to hold its first meeting.
