A poll has shown voters are divided on whether the Government Communications Securities Bureau spies can be trusted.
Fifty per cent of voters trusted the GCSB spies, 40 per cent of voters thought spies at the GCSB could not be trusted, and 11 per cent did not know, the TV3-Reid Research poll showed.
National supporters are the most trusting, with 60 per cent of those polled saying they trusted the agency's spies to act in the best interests of New Zealanders.
Just 36 per cent of Labour voters said they had faith in spies at the agency.
Green Party voters were the least trusting of the GCSB, with 60 per cent saying they did not trust the agency.
Mr Key said today GCSB spies could be trusted.
"They made a mistake when it came to the Kim Dotcom case - they got it wrong and what that review of GCSB has shown is that there is an inherent weakness in the organisations that we need to fix.
"My job as both the Minister and the Prime Minister is how we fix that organisation, how we strengthen it.
"What is without doubt is that New Zealand needs that organisation.
"Most New Zealanders would accept that we don't live in a risk-free world,'' Mr Key said.
Issues over the GCSB have dominated recent polls after a leaked report into the GCSB showed the agency had possibly illegally spied on about 88 New Zealanders on behalf of other agencies.
Prime Minister John Key then released plans to allow that kind of espionage.
Mr Key also confirmed he had directly contacted a school acquaintance, Ian Fletcher, to apply for a job as head of the agency.
In the same poll 48 per cent of voters said internet magnate Kim Dotcom should be allowed to stay in New Zealand - 42 per cent say Dotcom should be sent back to the US, and 10 per cent didn't know.
Most Green Party supporters surveyed said they wanted Dotcom to stay in New Zealand - with 65 per cent of Green-voting respondents saying he should stay, alongside 61 per cent of NZ First voters.
The questions in the poll said: "The Government Communications Securities Bureau the GCSB is responsible for defending New Zealand against an increasing number of cyber attacks, but it's been caught up in controversy, including potentially illegal spying on 88 people including New Zealand citizens and residents. Can our GCSB spies be trusted to act in the best interests of New Zealanders?''
"Kim Dotcom is fighting extradition to the United States to face copyright charges and wants to stay in New Zealand. Should Dotcom be sent back to the United States, or be allowed to stay in New Zealand?