The Privacy Commissioner has referred Immigration New Zealand's treatment of an Ethiopian refugee to the Director of Human Rights Proceedings.

The man had no record of his birth, and arrived in New Zealand in 2011 with incorrect information on his travel documents.

Two years later, he underwent a bone density scan and dental examination to clarify his age, which indicated he was possibly as old as 18 at the time.

The man asked Immigration New Zealand to change his year of birth from early 2000 to 1996 but it refused, and added a note to his file instead.

Privacy Commissioner John Edwards said the incorrect date restricted the man from accessing a number of entitlements, including the adult minimum wage.

Mr Edwards said Immigration had breached the man's privacy by failing to correct his date of birth.

"The Privacy Act has a right to correct information. Immigration New Zealand has said 'we can't correct that - that's your identity', and I'm saying 'well, that's not good enough'."

Mr Edwards said the man's parents died when he was young, there was no record of his birth, and his sponsor had the Ethiopian government issue a birth certificate saying he was born in early 2000.

"Here's a guy, through no fault of his own, has had an inaccurate record presented by a developing country or a third world country.

"Immigration New Zealand has been presented with evidence that the information is wrong, and they're refusing to adjust the official record."

Complicated case

Mr Edward acknowledged the refugee's case was complicated, but he says Immigration's systems should be able to accommodate individual circumstances otherwise individuals get crushed by bureaucracy.

"Their inability to deal with the reality of people who come to us from countries that are affected by civil war ... basically failed states, it's too much to expect that they bring correct official documentation that can be relied upon for all purposes."

The Refugee Council of New Zealand said the circumstances of the man's case were not uncommon and they dealt with a number of refugees who needed their names and dates of birth changed.

Vice-president Arif Saeid said Immigration interviewed refugees before they arrived in the country, and it was during this time they should be able to check people's personal details.

Dr Arif Saeid said Immigration then had a second chance to get things right, during the processing of a refugee at the Mangere Refugee Resettlement Centre.

He said there may be an underlying issue with the man soon becoming eligible to be a New Zealand citizen.

"Within five years, they can apply for citizenship so they get New Zealand passport. Probably this is the reason why he wants a big change now."

Immigration lawyer and member of the New Zealand Law Society Rob Davidson said it was not realistic to expect a refugee that arrived from Ethiopia in 2011 to now gain official and accurate documents from their birth country.

Immigration New Zealand refused to be interviewed, but they did issue a statement that said they did not believe they had breached the man's privacy.

"The individual's official identity document, i.e. his Ethiopian passport, is the cause of his situation.

"If his official identify document still shows his date of birth as early 2000, the remedy lies in the amendment or replacement of his passport.

"A person's date of birth is a fundamental cornerstone of identity and should not be able to be "corrected", unless through verifiable accurate records - Immigration New Zealand cannot and should not rely on a "best guess"."

Mr Edwards said by taking the refugee's case to the Human Rights Commission, he hoped Immigration's system would be changed to make them more flexible.

He said the case was about making Immigration do the decent things and recognise in these exceptional circumstances their rules need to bend.