Simon Hennessey, who was jailed for the murder of his aunt, fled British prison in 1998 and came to NZ.
Killer used false passport to fly freely between New Zealand and Australia.
A British killer flew in and out of New Zealand on a false passport 19 times before he was arrested in Australia for fraud.
Simon Hennessey was jailed in 1978 for the manslaughter of his 72-year-old aunt, Mary Webber. He escaped from a British prison in 1998 and somehow fled to New Zealand.
The 51-year-old was arrested in Australia in April 2013 on 50 charges of fraud. He admitted to Queensland police he had been using a false passport.
In 2010, he had applied for a passport in the name Robert Eric Jeffrey, a Hastings man who lived in a care home since suffering severe brain damage in a car crash.
Now, new documents released under the Official Information Act reveal he flew in and out of New Zealand 19 times on that passport from 2010-2013.
Police could not rule out his having committed other offences in that time. The heavily redacted documents also reveal the Department of Internal Affairs (DIA) had no photos of Hennessey or Jeffrey on their system.
DIA could not run photos supplied by Queensland police through facial recognition software because the system was not working.
In an email to Interpol, investigator Ian Tingey said: "It should have been operational about three months ago, but we had some installation issues.
"We are hoping our IT will have it sorted next week ... So bottom line, we can help but it may take a month before we run the images through the system."
A spokeswoman for DIA said when Hennessey applied for the passport, the department was not using the software.
"Since the Hennessy application the facial recognition system has been implemented."
The emails also reveal a person obtained two birth certificates before helping Hennessey apply for a passport by signing the witness section.
A Department of Internal Affairs spokeswoman would not say if that person had been investigated or prosecuted.
However, she confirmed no other New Zealand passports were issued to Hennessey. "Our passport is a world-class, highly secure, trusted travel document with a strong international reputation," she said.
Hennessey is back in custody in the United Kingdom where he will continue serving his life sentence.