A convicted murderer and child sex offender is challenging being labelled a "psychopath" as he heads toward his first parole hearing after 13 years in jail.

Phillip John Smith's lawyer, Tony Ellis, told a High Court judge yesterday that if Smith was shown to have a history of psychopathy his chance of getting parole was "not good".

The procedure leading to the assessment was not properly done, Mr Ellis said.

"In essence you need a good psychological report to get out, and if it is tainted by all this it is not going to happen."

Smith was ordered to serve at least 13 years of a life term for murdering a man in the Wellington suburb of Johnsonville in December 1995. He had been due to go before the Parole Board in March, Justice Forrie Miller was told yesterday.

Smith had been sexually abusing a young boy in Wairarapa and, while on bail for those charges, tracked down the boy's family after they moved to Johnsonville, and stabbed the boy's father to death. The dead man was not identified to protect the abused boy.

In October 1998, a psychology intern interviewed Smith, leading to a report early the next year that was put on his prison file.

That intern - who was repeating his intern year because he failed his diploma the first time - and another intern assessed Smith against a psychopathy check list, and concluded he was a "borderline" psychopath.

Mr Ellis said there was no evidence that Smith was told of the assessment being done, nor was he given the result.

"Unbeknown to him, and in secret, a further assessment is done and it is one of the most significant things that could be done on any person in prison life."

Once Smith had been labelled a psychopath it had very serious consequences and had affected every decision made about him in the prison system since then, he said.

Smith had asked to see a psychologist for treatment.

David Wales, the assistant director of the Corrections Department's psychological service, said the assessment was one way to identify areas to direct treatment.

The department is opposing Smith's case and the hearing continues today.