The SIS is warning the 40 people on a terror watchlist in New Zealand have become more determined and capable since the Paris attacks.
And it could not rule out that up to 12 New Zealand women who have gone to Islamic State-controlled areas in Syria and Iraq in the last 12 months were jihadi brides.
SIS director Rebecca Kitteridge told MPs at the annual intelligence and security committee meeting the development over the past year was new and alarming. She would not provide numbers but said it was fewer than a dozen.
There are about 40 people on a terror watchlist here, including one or two under 24 hour surveillance, and Ms Kitteridge told reporters the Paris attacks had caused a lot of excitement. She said sometimes the worse the attack the more excited they became.
Ms Kitteridge yesterday reported back to the intelligence and security committee, which is chaired by Prime Minister John Key.
She told the committee that terror incidents could have the opposite effect they would have on an unradicalised person.
"These incidents overseas that occur that are so horrifying, if you're you or me, they act like a kind of exciting factor for these kind of people," she said.
She also told the committee that the country was seeing, for the first time, New Zealand women travelling to Islamic State-controlled areas in the Middle East.
"It's difficult to see what they do when they go. We definitely do have intelligence that they went. Whether they are going to fight or whether they are going to support other fighters is not clear."
Mr Key told reporters he was aware of some cases.
"There's certainly a few women that have left, engaged in these weddings effectively at the very last minute, and gone to Syria, and all of those factors would point to the fact that they're going as jihadist brides."
Labour's leader Andrew Little said the problem was not just about radicalised women leaving New Zealand but what happened if or when they came back.
"I think the issue is with Daesh, and their attitude towards women generally, they're fundamentalists, they're antediluvian, I'd be more concerned about that.
"And equally concerned about those who fall under the spell, go, and then wanted to come back and what they may well bring back and we do need to be alert to that."
The head of the Federation of Islamic Associations, Hazim Arafeh, said he was very surprised by the revelations - but he had no choice but to believe it.
Mr Arafeh told Morning Report he was surprised by the claim for several reasons, including New Zealand's distance from the conflicted areas.
"We all believe that life in New Zealand is much more attractive than going in to join an extremist ideology."
Mr Arafeh says he was in touch with security services regularly, and his organisation was monitoring a handful of people it considered to be of concern.
"If there is anybody who thinks that this ideology is attractive, they should be contacting their nearest mosque or the Federation, because we have got people to help anybody who has been mislead in the past."
Terrorism 'equal-opportunity employer'
Meanwhile, a security analyst said Ms Kitteridge's revelation was unwise.
Paul Buchanan, from 36th Parallel Assessments, told Morning Report he was not surprised that women are among the 40 people being monitored by the Government.
But he said the women were an exploitable resource for tracking, so revealing the security services were aware of them jeopardised their ability to monitor them.
"I don't want to be too cynical, but I think that events in San Bernardino, and the role of the woman in that massacre, may not be entirely concidence with her decision to reveal this, simply because we do have a jihadi bride involved, although the circumstances of the woman in San Bernardino are very different."
Mr Buchanan said it was very unlikely any of the women would return to New Zealand.
Victoria University professor of strategic studies Robert Ayson said he was also not at all surprised that New Zealand women were also travelling to join Islamic State.
"You know, you've seen in some situations overseas, suicide bombings and other areas, that sometimes women have been willing to do this as well as men have been willing to do this.
"I don't think you'd say that ISIS is an equal-opportunity employer but sometimes terrorism can be."
The possibility some of the women may have gone over to fight against Islamic State, or to join another extremist group, could not be discounted either. Some people had a perverse attraction to terrorist groups such as ISIS and the excitement and feeling of power that provided, he said.
"In a world where perhaps people's lives are fairly mundane and ho-hum, where they perhaps don't feel much excitement in their lives.
"There is something that is somewhat glamourous for some people about the ability to break all the rules that you can possibly break and to cause wanton violence."