"Obviously we are hugely relieved she is safe and sound but obviously you are always concerned for your children and your family members and this is a time when there is a great deal of uncertainty in Paris. There may potentially still be some of these terrorist at large so that presents risk."
Mr Key, who had just landed in Darwin on the way to Vietnam, said the he felt "numb" after hearing the news and expected others would too.
"It's a tragic day for the people of France and for any of the families of the victims involved."
"Our hearts go out to those involved and our thoughts with them and their families," Mr Key added.
"New Zealand stands with France in the global fight against terror and while it is too soon to attribute blame, the attacks have targeted innocent civilians and are therefore an act of terrorism.
"French authorities have not yet released the nationalities of any of the victims but consular officials in Paris and New Zealand are working to determine if any New Zealanders have been caught up," he added.
He said there had been no information of New Zealanders caught up in the attacks at this stage.
He said Kiwis in Paris should make contact with their families - as Stephie Key had reached out to Bronagh when news of the attacks broke.
"It's the time that you always feel that distance between your own family members and somewhat helpless that there is not a hell of a lot you can do.
"She was out at a shopping mall. One of our friends saw an update on the British media and then she texted my wife who then got in contact with our daughter and my wife rightly advised her to get home to her apartment as quickly as she could."
Mr Key said Stephie wouldn't be asked to return to New Zealand. "We'd tell her obviously to keep herself as safe and secure as she possibly can but obviously she's in the same position of millions of others living in Paris."
He said those with concerns about friends and family in France could make contact with the Ministry of Foreign Affairs or the New Zealand embassy in Paris.
Key described the attacks as "a coordinated series of terrorist attacks taking place in multiple locations" and an illustration of why terror had to be resisted.
"It is particularly vicious in nature. If you think about the reports we see coming from the concert hall, it is utterly brutal terrorism which has clearly been undertaken in a way to terrify people.
"It is both troubling and disturbing and I think shows people why we have to stand up to these terrorists because they know absolutely no bounds when it comes to humanity."
Mr Key said he still intended to attend the COP 21 climate change conference in Paris in December. "I think you'd imagine the French authorities would want to continue to hold COP21."
Little: 'It is horrifying'
Labour leader Andrew Little said the attacks were a "horrifying" assault on innocent civilians.
"This is now indiscriminate killing [targeting] members of the public. It is horrifying."
Mr Little said French authorities would have to ensure security was "absolutely watertight" ahead of the United Nations Climate Change Conference starting on November 30.
Mr Little said he was confident domestic intelligence organisations including the GCSB and SIS were doing the best they could, with the tools they had, to monitor possible terrorist threats in New Zealand.
"We know that there are people in New Zealand who see these sorts of things happening in the media and for whatever reason they're motivated to act out...in copycat-type sort of behaviours.
"Although the risk of something of the magnitude of what's happened in Paris is pretty low, you can't necessarily plan for a slightly unhinged (person) thinking it's time for them to do something and make a name for themselves."
He told NZME News Service New Zealanders travelling in Europe might encounter a culture where some civil liberties were curbed in the wake of the attacks.
"That's the price we end up paying until we find an answer to whatever the underlying issues and causes are."
Mr Little has expressed his concerns following the terrorist attacks.
"It's obviously a tragic situation for the families involved and a real worry, in security terms, that something like this could happen."
Mr Little acknowledged the attacks - which killed up to 150 people today - came as locals were still recovering from the Charlie Hebdo terrorist attack, in which 12 journalists were killed in January.
He said many people in the region would be wanting to know that security had been bumped up.
"Of all the cities you'd expect to be on alert, after the events at Charlie Hebdo, you'd think that they'd have the means to prevent something like this.
"But that hasn't happened and so it raises issues about what is needed to keep the public secure,'' he said.
"People will be wanting to know that the French authorities can provide proper security for people.''
The New Zealand Ministry of Foreign Affairs and Trade has confirmed the number of Kiwis registered as being in France has risen in the past few hours from 249 to 279.
A spokesman said they have had no reports so far of any Kiwis being injured.
A safe travel alert issued by MFAT this afternoon has since been reviewed but is unchanged, a spokesman said.
"There is an unfolding security situation in Paris with reports of several shootings/ explosions in separate incidents occurring simultaneously in the 10th and the 11th districts, and near the Stade de France, with early accounts indicating at least 40 deaths. There are also reports indicating a hostage situation involving at least 60 people in a theatre in Paris," the update said.
"The French President has declared a State of Emergency and security forces have been deployed in Paris. As a precautionary measure, French borders have been closed.
"New Zealanders in Paris are advised to stay indoors and keep themselves informed of potential risks to safety and security by monitoring the media and other local information sources. You should also contact your family in New Zealand to advise them that you are safe.
"New Zealanders in France are strongly encouraged to register their details on SafeTravel."
New Zealanders who require consular assistance are advised to contact the New Zealand Embassy in Paris on: 01 45 01 43 43 (from within France) or +33 1 45 01 43 43 (from outside France).
Anyone with concerns about a New Zealand family member in Paris should try to make direct contact with them in the first instance. If they had ongoing concerns, they should contact Mfat.
Tap here to go to the MFAT site.
Air New Zealand has confirmed flights in and out of France may be interrupted due to heightened security measures in Paris.
Flexibility will be permitted on all fare types for Air New Zealand passengers scheduled to travel to and from all French airports until Friday, November 27, if they are ticketed for travel prior to and including Wednesday.
Various options are available for passengers to defer or bring travel forward, or change their destinations, the company posted on Twitter.
