A convicted paedophile travelling on a New Zealand passport may be deported from Thailand following his arrest on suspicion of child sex offences.

Peter Dundas Walbran has been in an immigration detention centre in Bangkok since his arrest on December 9

Sky News Australia reported the deportation is expected to take place late on Friday as Thai police re-examine digital media recovered from his apartment on the day of his arrest.

If they find anything illegal on his hard drive, they could have him extradited to New Zealand, Sky News reported.

Advertisement

Walbran, 59, of Sydney, was arrested at the secluded Narinukun international school 616km from Bangkok where he had been working as a teacher. Police had been tracking him for 18 months after receiving a tip the school had hired him in May and he was overseeing its 70 international students. The school has 4000 students on its roll.

In October 2011, Walbran, a former head of the Australian International School in Jakarta, was extradited from Australia to Indonesia following a request by the country's government.

The next year he was jailed for the rape and molestation of Indonesian boys, some as young as 8.

He served two years of a three-year sentence before being deported back to Australia in April last year.

Walbran then flew to Thailand through New Zealand, using a Kiwi passport, which enabled him to avoid Australian travel alerts for convicted paedophiles. He also failed to complete the process of registration with Australia's National Child Offender Register, Thai investigators told AAP.

Prime Minister John Key said at the time he didn't know how Walbran obtained a New Zealand passport.

"My advice at this stage is Mfat [Ministry of Foreign Affairs and Trade] doesn't know about the individual," he said.

"It's quite possible that it's legitimate. There are people that [sic] have multiple passports because they have multiple citizenship. So there are lots of people who travel on both an Australian and New Zealand passport and might theoretically do that at one time.

Advertisement

"But if it's an illegal passport, that's a very different issue but I don't have any advice about that."