Canadian authorities are investigating why alleged agent Uriel Kelman - then a serving member of the Israeli Defence Force - used a Canadian passport to visit New Zealand in 1999 instead of travelling on his Israeli papers.

Kelman - now a civilian - used his Israeli passport to travel to New Zealand late last year and again this March, before being caught by police trying to unlawfully obtain the passport of a young New Zealand man with cerebral palsy.

Canadian Foreign Affairs spokesman Reynald Doiron said inquiries had not revealed any similar attempts to get Canadian passports for illegal purposes.

But they were concerned that a serving member of the Israeli Defence Force had travelled under Canadian papers.

"Should that turn out to be the case we would not appreciate it," said Mr Doiron.

"We have to wait until various departments and agencies have completed their investigations before any confirmations of that or any actions stemming from that is envisaged."

The authorities' investigation, including an inquiry by Canada's intelligence services - began after police gave evidence to a court hearing in April that Kelman used his Canadian papers to enter New Zealand in 1999.

Mr Doiron confirmed that inquiries by Canada's Passports Office had found Kelman was born in Canada and was entitled to a Canadian passport.

At a depositions hearing in Auckland police revealed Kelman travelled on his Canadian passport to New Zealand in 1999 and left eight weeks later on a replacement passport.

"That one expired and he did apply and obtain a replacement passport which corresponds to the second passport whose number was quoted in the case," said Mr Doiron. "So those passports are legitimate."

Canada got an undertaking from Israel that its passports would not be used for undercover purposes after a botched attempt to target a top Hamas official in Jordan in 1997 in which Mossad agents were found to have used Canadian passports.

"What happened in 1997 and what might have happened in this particular case do not compare, to the best of our knowledge."

Kelman is appealing his conviction in the High Court at Auckland this month for taking part in an organised crime group with Eli Cara, who is also appealing his conviction, in an attempt to unlawfully obtain a New Zealand passport with Zev William Barkan, 37, and a fourth person.