A Nigerian drug smuggler who duped authorities to get a job in New Zealand as a hospital psychiatrist came across as friendly and plausible, but secretive, acquaintances say.

Chidozie Emmanuel Onovo, 40, lived in Christchurch - next door to a senior policeman - and worked for the Canterbury District Health Board from January 2009 until August this year, after failing to disclose he had been jailed in Britain in 1999 for importing 4.5kg of cannabis.

He has been a member of the Christchurch Skeptics in the Pub group, which among its core activities studies "mechanisms of deception". Onovo said the group offered "excellent opportunity to meet like-minded people".

He had spoken of his desire to bring his wife and children over from Ireland to live with him, but on Wednesday was jailed for 16 months for failing to disclose his criminal past.

He obtained a visa to enter New Zealand in January 2009, then a work permit to get the job as a psychiatrist. It was not until August this year, after Onovo applied for residency, that immigration checks found him out.

He had supplied forged reference letters saying he was working in the medical field in Nigeria over a period in which he was in jail in Britain.

Dawn Catherwood, whose daughter rents a townhouse to Onovo, had him over for meals and found him to be plausible and a "really nice guy". He paid his rent on time, but had recently terminated his lease and was planning to go overseas.

Earlier this year he visited his wife and children in Ireland.

"He had lost a lot of weight since he had been in New Zealand - we noticed that. And he was hoping to bring his family out here."

Often he was not at home when arranged meetings were meant to take place, she said. "He's very secretive. He doesn't let anybody into his flat."

Inspector Kieren Kortegast was a neighbour of Onovo, but said he only spoke to him a couple of times and rarely saw him.

He was surprised to hear of Onovo's deception.

Immigration New Zealand said it was their inquiries that revealed Onovo's criminal past, while the health board said it went through the required processes and routine checks before employing him and there were no concerns about his competence.

The Medical Council said Onovo met all the registration requirements to work in New Zealand and had references showing he was a good doctor.