The young Israelis at the centre of suspicions of spying and attempted passport fraud were merely backpackers, Prime Minister John Key says.

Suspicious behaviour prompted an investigation into whether four young Israelis caught in the February 22 earthquake in Christchurch were linked to the Israeli intelligence agency, Mossad.

One of them was killed, and the three survivors fled the country within 12 hours, the swift departure attracting the attention of New Zealand officials.

As they departed, two Israeli teams arrived in Christchurch: an unaccredited urban search and rescue team that was escorted from the CBD after they were found in a restricted area, and a forensics team that allegedly had access to a national police database.

"We had a scenario where we couldn't be sure, we undertook a full investigation," Mr Key said yesterday.

"It didn't turn up any information [of a link to Mossad] ... and on that basis we left it at that.

"We don't expect Israel to [spy on us], but we have no evidence to support that they have. We simply had a very unusual set of circumstances."

Mr Key said the Government did not raise the issue with the Israeli Government because there was no evidence of illegal behaviour.

However, he was careful with his language, indicating that he could not categorically rule out the possibility.

"On the information we have, there is no link between these individuals and the Israeli intelligence service."

The Herald understands the Government raised the matter of the search and rescue team with the Israeli ambassador, Shemi Tzur.

The presence of the team was against the policy of using only UN-accredited groups.

Mr Key, who is in America, initially refused to comment on the issue, but later said the police and the Security Intelligence Service launched an investigation and found no evidence of inappropriate activity.

He rejected earlier claims that the man who died, Ofer Mizrahi, had five passports - although the four Israelis had five passports among them.

Mr Mizrahi had his European passport on him and his friends handed his Israeli passport in before they left the country. Neither Mr Mizrahi nor his companions had New Zealand passports, Mr Key said.

He had not asked Israeli officials if the Mossad intelligence agency was spying on New Zealand.

The Security Intelligence Service has reportedly audited the police national database on the suspicion that the Israeli forensic team may have been trawling it for identity information.

Mr Key said the team had worked in the morgue, but did not have access to the database. Police said they were confident their systems were secure.

New Zealand passports are considered to be highly coveted by international intelligence operatives, given the nation's neutrality in world affairs and the relatively easy access the document allows to other countries.

In 2004, two Israeli spies were detained at Auckland Airport and later convicted of passport fraud, sparking sanctions from then-Prime Minister Helen Clark. Diplomatic relations were only recently fully restored.

Mossad agents have previously used false passports in assassinations.
Global security expert Paul Buchanan said it was "credible" that the group of Israelis were in Christchurch for more than just a holiday, but the evidence was circumstantial.

It was plausible that the men were "trolling", meaning they were looking to steal identities to clone a New Zealand passport.

He said they were too young to be Mossad agents, and were more likely sayanim ("helpers" in Hebrew).

He suggested the Prime Minister's initial reluctance to talk about the issue was to protect Israel from any fallout from a public stoush and ensure the continued sharing of intelligence.

Opposition parties called on Mr Key to name and shame any countries which had sought to abuse New Zealand's sovereignty.

Labour leader Phil Goff said there were still many unanswered questions.

"Was there an attempt to break into the police computer system? Why did the other companions of the man who was killed leave so suddenly? What was the Israeli search and rescue team doing in an area where it wasn't allowed to be?

"The suspicion is that this is a cover-up to avoid embarrassing Israel."

Ambassador Tzur has said claims that the Israelis were spying were nothing more than "science fiction".

* An Israeli man who died in the February quake had at least five passports on him.
* Israeli Prime Minister Benjamin Netanyahu called John Key four times on the day of the quake.
* Unaccredited Israeli search and rescue team was escorted from the red zone in the CBD.
* An Israeli forensic analysis team working in the morgue may have accessed the police database.

* The Israeli killed in the quake had only one passport on him - and it was not a New Zealand one.
* The Prime Minister and his Israeli counterpart spoke only once after the earthquake.
* An investigation found no evidence that the Israelis were linked to intelligence operations.
* There was no reason to believe the police database was breached.