A critic of the country's spy agencies doubts they can be trusted with expanded powers coming their way in new intelligence laws

United Future Leader Peter Dunne said provisions that will give SIS and GCSB staff immunity from criminal liability are amongst his concerns, though he accepts there will be situations where it would be desirable.

But he believes they have an attitude that the law is a minor irritation they treat as they see fit, and he thinks they've read too many Le Carre novels.

"I just don't think that they're sufficiently clear of that attitude to be confident that they could act responsibly under the type of environment being proposed in this bill."

SIS and GCSB Minister Chris Finlayson said how criminal immunity is determined, and by whom, could lie with the courts.

"If there was an issue that arose, ultimately that would be for a Court of law to determine, based on the evidence, if it ever got that far."

Peter Dunne is also calling for Parliament and the Government to more firmly set the direction for the country's intelligence services.

"I'd like to see us get to the point where the government tabled a policy statement each year. it doesn't have to be totally specific but [along the lines of] these are the priorities we see for the security services. At the moment, the security services largely determine their own priorities."

But Minister Finlayson is taking issue with some of the comments Mr Dunne's made, specifically around the Bill's definition of national security - an issue he argues is covered in the legislation.

"I'm just a little bemused that Mr Dunne has put out a press release saying there's no definition of national security in the bill, but we'll work that one through in a patient and professional manner."

The legislation is likely to pass its first reading, with Labour indicating that they will not oppose it at this stage.

New Zealand First leader Winston Peters wants to see public feedback on it at Select Committee, but he's making no long term commitments.

"You've heard the old saying - only a fool would test the water with both feet. Well we'd like to know what the public, and other people who have got some expertise think of this legislation."

The first reading will take place on Friday.