Prime Minister John Key says every country in the world is vulnerable to a terrorist attack but New Zealand is probably less vulnerable than most others.
He also said that being a member of the Five Eyes Club - the intelligence alliance with the US, Britain, Canada and Australia - also gave New Zealand an advantage in terms of monitoring suspects but terrorists were getting more sophisticated.
Speaking to New Zealand reporters in Hanoi, he said he would not characterise the Paris terrorist attacks on Saturday at the weekend as a failure of intelligence.
"I wonder whether the right characterisation isn't that they failed but that the terrorists are becoming more sophisticated and quite a lot of the communications they have are what, in the business, we would call dark. In other words we can't actually monitor them."
Some of the media reports he had seen indicated there had been no conversations by the perpetrators that had been conducted on anything that remotely looked like an open line.
"That's what we have got to get a bit more attuned to - that we cant be 100 per cent sure we can cover everything."
He said NewZealand's watch list was still about 40.
"I think every country in the world is potentially vulnerable. We are probably less vulnerable than most others."
New Zealand had the advantage of distance.
"We are a long way away. I just couldn't say to you we are completely immune. We have people on our watch list. We know that Isil are very effective reaching out to those people.
"We have a responsibility to other New Zealanders to do the best we can to monitor any behaviour that we think is unusual or untoward.
"We cant guarantee we get on top of all of that. These people are quite sophisticated in the way they communicate with each other. But we are certainly a lower risk environment than many other parts of the world."
New Zealand has committed about 140 Defence Force personnel to jointly run a training operation with Australia at Camp Taji north of Baghdad to help equip Iraqi forces in their fight against Isis.
Australian Prime Minister Malcolm Turnbull reportedly talked about sending "peace-keepers" to Iraq and Syria but Mr Key said he was not contemplating that.
"I wouldn't want to put our people out there either unless I was convinced that it was actually safe to do that reconstruction work," Mr Key said.
Over time, clean-up skills and reconstruction would definitely be required if there was a successful political solution.
"New Zealand has got a lot of skills in that area but that's not where we are at the moment."
- By Audrey Young in Hanoi