A man who committed a knife-point rape of a 15-year-old girl he plucked off the street has been jailed for 13 years.

The offence happened as the girl was waiting for her father to pick her up in the early hours of the morning in Mairangi Bay on April 6 last year.

Benjamin Barrie Bradbury, a 28-year-old labourer, was found guilty by a district court jury on charges of rape, abduction, indecent assault and possession of a knife.

In the High Court at Auckland yesterday Mark Davies, for the Crown, unsuccessfully sought preventive detention for Bradbury, whose offending occurred eight months after his release from prison for indecently assaulting a 6-year-old girl.

Bradbury, he said, committed random sex assaults on several young women. The weekend before the April rape he had indecently assaulted three other teenage girls.

Justice John Priestley told Bradbury, who will have to serve a minimum seven years, that if he ever offended again he could be locked away for the rest of his life.

He said that Bradbury tended to regard women who were strangers as objects for his sexual gratification.

He had no qualms about interfering with the young women, and a week later snatched another victim off a street. He forced her into his house, made her strip and raped her while threatening her with a knife.

The judge said that Bradbury testified at his trial that the sex was consensual, though he had never met the girl before, but the jury disbelieved his fabricated story.

Peter Kaye, defending, said that Bradbury still maintained his innocence.

Justice Priestley told the rape victim and her father, who were in court, not to blame themselves.

What happened was a parent's worst nightmare, he said, and his heart went out to them.