A teenage girl has been sentenced to seven months' jail for falsely accusing three young men of rape.

It was the second time in less than a year that Kristie Tayna Jenkins had lied to police about being sexually assaulted, Judge Michael Turner said when sentencing the 18-year-old in the Dunedin District Court yesterday.

Jenkins last December admitted she made an untrue sworn statement which would have amounted to perjury if given in evidence at a court hearing. In the statement, made on May 26, she claimed three young men she knew had sexually violated her in South Dunedin 13 days earlier.

The complaint triggered an investigation involving the interviewing of the three suspects, all of whom denied the allegations. One of the men told police he and Jenkins had consensual sex about five weeks before the date of the alleged rape.

When police spoke to her last November, having decided her complaint was untrue and there was no basis for any charges to be laid, Jenkins was unco-operative and abusive and refused to speak about the matter.

Public defender Catherine Ure described the defendant as young, immature and naive and characterised her behaviour as "attention-seeking'' and without malice. Jenkins had not expected the matter to go so far, Ms Ure said.

But Judge Turner said the defendant had made a false complaint of rape, had undergone an extensive medical examination and had never retracted her statement.

And it was the second time in a year she had done the same thing.

On the first occasion, Jenkins was given a nine-month deferred sentence for making a false statement a crime had been committed.

Ms Ure said the current offence had started as an untruth and had grown from there. The defendant was very frightened about what would happen to her.

A prison term would have serious long-term effects which would follow Jenkins for the rest of her life, counsel said.

The false statement Jenkins made in 2014 was that she had been raped by her boyfriend. Police took the complaint seriously and investigated it, Judge Turner said. But, a month later, with no explanation, the defendant told police she wished to withdraw the complaint.

One of the three young men she had falsely accused this time had been "sickened'' by her behaviour, Judge Turner told Jenkins. The young man said the accusation had put a black mark against his name.

He said he knew a couple of "real'' rape victims and had the utmost empathy for them and he described the defendant's behaviour as "a disgrace''.

At 18, Jenkins had an unstructured lifestyle with self-reported but unverified mental health issues, the judge said. A probation officer assessed the likelihood of her re-offending as low but Judge Turner said he was "not sure how that can be'' given she had committed a similar crime only a year earlier.

In his view, the gravity and seriousness of the offending was high, and the consequences of the false accusations were potentially very serious for the suspects.

Had a prosecution followed and the three men been convicted on Jenkins' false evidence, they would have faced lengthy prison terms. What she had done struck at the heart of the criminal justice system, Judge Turner said. She had made a false complaint and carried on with it and innocent men were subjected to a police investigation.

Only as a consequence of the police assessment of the situation and their decision it could not be correct did the case go no further. Jenkins had done nothing to put matters right at any stage.

Counsel described Jenkins as a naive and inexperienced young person, but the judge said he did not accept that. And he had detected no real remorse expressed by her.

Judge Turner sentenced the defendant to seven months' jail but, taking into account her youth, gave her leave to apply for substitution of home detention when a suitable address became available.

After the sentence expires, Jenkins will be on six months' post-release conditions with a substance abuse assessment and counselling, treatment and programmes as recommended.

Judge Turner made an order permanently suppressing the names of the three young men falsely accused by Jenkins.