PM won't rule out using SAS against Isis

Prime Minister John Key won't rule out sending New Zealand's elite SAS personnel to assist US efforts to counter Islamic State (Isis) militants in Iraq or even Syria but says that would be done reluctantly as a last resort, if at all.

Mr Key also confirmed New Zealand was assessing its security alert following recent reports of a terrorist plot in Australia and that he was seeking advice about New Zealanders fighting for groups like Isis who want to return home.

New Zealand has been named by the US State Department as one of more than 60 countries in the coalition supporting its efforts to counter Islamic State, according to a report in the Washington Post.

Mr Key said this afternoon New Zealand hadn't at this stage received any requests for assistance but nevertheless, "I would expect to get some advice on what are the options available to New Zealand but obviously we couldn't act on those even if we wanted to in the short term because we're in the caretaker mode (until the new Government is sworn in) ".

Asked specifically about sending military personnel to assist, Mr Key said: "I can't rule out that there won't be because what you can see around the world is countries being asked to give support.".

"Now what New Zealand's best form of support might be if we were willing to do that is at this stage undetermined but I guess what I would say is that if people were looking for me to push the green light, if you like, on being much more aggressive in terms of commitment of resources to Iraq I think they should take a step back because it would be a very last resort."

As far as sending SAS personnel Mr Key said "I can't rule that absolutely out but what I can say is that I'll get advice and we'll see how that goes but it would be my least preferred option."

Any commitment of personnel "would be a step I think we should take very cautiously and with our eyes open because history tells you that going into places like Iraq are fraught with difficulty and danger and as we know with Afghanistan it was a very long term commitment".

"So I'm not saying absolutely no but what I'm also saying is it's something we would treat very very cautiously."

Watch: Key: NZers' looking to fight with IS

Mr Key again emphasised involvement in Iraq, where the Government there had asked for international help, was more likely than in Syria where that was not the case.

Despite his clear reluctance for New Zealand to get involved in military operations, Mr Key said he was of the view that airstrikes on Isis targets in Syria and Iraq"will only take you so far".

However, the conflict in Afghanistan had shown such commitments were neither easy or shortlived and the sophistication of Isis was greater than the al-Qaeda linked Taleban there.

Meanwhile, following recent events in Australia including raids targeting an alleged Islamic extremist plot to behead a random member of the public, Mr Key said security agencies were "looking at the overall threat risk in New Zealand" and assessing whether it should change.

He was also taking advice on whether New Zealand would follow Australia's lead and begin publicly notifying its threat level.

Mr Key said New Zealand was aware both of New Zealanders looking to leave this country to fight for groups like Isis, and of some who were already doing so but who may want to return despite having their passports revoked.

He understood current law meant it was unlikely they could be prosecuted if they did return to New Zealand and again that was a matter under consideration.

However the bigger issue was monitoring those people's movements and how they might return to New Zealand without travel documents.