Recommendations from a review of New Zealand's spy agencies would ensure they have a much more structured way of doing things, public law specialist James Dunne said.
The recommendations would loosen current restrictions on the ability of the Government Communications Security Bureau (GCSB) to carry out surveillance on New Zealanders.
The proposed new laws would allow such surveillance but only for the purpose of protecting national security, and under warrant.
The review recommended that the GCSB and the State Intelligence Service (SIS) be governed by a single law so their purposes and boundaries are clearer.
Mr Dunne, of Chen Palmer law firm, told Morning Report the GCSB already had the power to assist other agencies, including the SIS and police, and it would be best to accept that they were the ones with the expertise to do such work.
Another issue of concern was how much the security agencies were an extension of foreign agencies, and the report suggested more controls were needed, he said.
"One of the things which the report looks at is actually trying to set out some more regular powers about what the security agencies have to do when they're helping a foreign agency, what they can't do, how they have to essentially put New Zealand first."
NZ 'closer to surveillance state'
Meanwhile, the Council for Civil Liberties said the proposed new 'merger' in spy legislation brought New Zealand one step closer to being a surveillance state.
The council's chairperson, Thomas Beagle, said people should be worried about government surveillance.
"I think it's part of a shift towards an overall surveillance society and I think it's part of a wider shift towards a government which is not of the people but a government which is actually working on the people."
It had been seen that the agencies had not always shown good judgement about who they spied on, he said.
He believed the risk of a terrorist attack in New Zealand was low.
Spy laws a balance - Key
Earlier, Prime Minister John Key said getting the spy laws right was a balance between national security, privacy and human rights.
The laws needed to be clarified and streamlined, he said.
Under current law, the GCSB could not spy on New Zealanders unless another agency asked it to.
But it had been acting very cautiously because it had got it wrong in the past, such as when it spied on internet entrepreneur Kim Dotcom.
Mr Key said the SIS would remain focussed on human intelligence and New Zealanders, as the GCSB focussed more on signals and intercepting communications.
The changes would not be an extension of the intelligence agencies' powers overall.
But United Future leader Peter Dunne did not agree.
"I think it is an extension in terms of the level of surveillance, I think there is clarification about the application of the rules and I've got not problem with that.
"But I think the bigger question is what is the nature of the organisation?
"I think if we are going to have a common statute, it seems to me there should be a common organisation and that provides a lot of opportunities to fine tune and thin down its size and scope."
Green Party co-leader Metiria Turei said there was no justification for expanding the powers of the GCSB.
"We shouldn't have the GCSB taking New Zealanders' information and sharing it a wide range of other countries, New Zealanders do not want to see their privacy eroded any more."
Mr Key said he wanted to work with other parties, Labour in particular, to get agreement cross-party agreement on new laws.
Labour Party leader Andrew Little said Labour would work with the government to get good legislation but he wanted a clear answer on whether the GCSB was getting more powers.