Prime Minister John Key is heaping pressure on Peter Dunne to vote for controversial spy legislation, as he scrambles to build Parliamentary support for the controversial bill.



The Government is working on legislation to extend the powers of the Government Communications Security Bureau (GCSB) to spy on New Zealanders, although Key maintains this simply formalises what has been happening for years.



With the Maori Party indicating it will not vote for the legislation, it will almost certainly rely on the support of Dunne or NZ First.



Dunne has expressed deep reservations about the bill, saying he wants a ''very clear boundary'' between the Security Intelligence Service (SIS), which focuses on domestic surveillance, and the GCSB, which focuses on foreign threats.

The GCSB should not spy on New Zealanders ''under any circumstances'', Dunne said.



But Key said this morning that he was ''extremely confident'' that Dunne, a Government partner, would vote for the bill.



''He knows the value of national security and he knows that we actually do need to clarify the law to allow assistance to be provided to the likes of the SIS and the police,'' Key told TV3's Firstline this morning.



''This is not a debate about whether a particular New Zealander will have intelligence gathered about them and about their activities. That will happen. The question is whether SIS do it or GCSB do it under a warrant provided by SIS as an assisting agent.''



The Government is prepared to work with New Zealand First on the bill, but Key said it was not unusual for National to work with the party.



NZ First leader Winston Peters has said that there has been a lack of analysis done on the bill, and that greater safeguards need to be put in place to monitor the GCSB.

Meanwhile Key indicated it was only the influence of Grant Robertson, Labour's deputy leader, stopping that party supporting the bill.

''Labour have got themselves in a bit of a terrible bind. They actually know that they need to vote for this legislation, they know it's increasing the oversight, but Grant Robertson's sort of running the ship around there. He's just playing politics with it and [David] Shearer's been rolled over by Robertson and that's the problem.''



Yesterday Key warned the surveillance capabilities of police, the SIS and Defence Force would be beefed up if controversial spy legislation falls over. That would be at "significant cost", Key warned.



In an unusual move, Key is set to chair some of the public hearings on the bill, which has attracted 121 submissions, some of them scathing about the sweeping nature of the legislation.



The Law Society says the bill will empower the GCSB to spy on New Zealand citizens and residents in a way that was not previously contemplated and was inconsistent with the rights to freedom of expression and freedom from unreasonable search and seizure.



But Key yesterday dismissed the complaint and said he did not agree the legislation expanded the mandate of GCSB.



Under existing legislation the GCSB is supposed to be used for foreign intelligence-gathering operations and is not allowed to spy on New Zealanders.



However, an inquiry revealed the GCSB had possibly spied on more than 80 New Zealanders illegally in the belief it was entitled to do so while acting under warrant from another agency like police, the SIS or Defence.