"You've kept your side of the promise, I will now keep mine," Judge Wade told Antolik. "I wish you well for the future."
But the Immigration Service is still investigating whether to deport him, and in an unusual move, the Crown may appeal against the discharge without conviction sentence.
A Crown Law spokeswoman in Wellington confirmed "we are considering whether or not an appeal would be made".
An Immigration spokesman said the department was "still assessing his case" but declined to comment further.
Antolik did not return messages.
Karel Sroubek came from the Czech Republic in September 2003 to start a new life as Jan Antolik. Sroubek, aged 22 at the time, and his family had been threatened by two police officers who wanted them to lie and clear the main suspect in a murder investigation. Instead, he left a videotaped witness statement, which was crucial in convicting the killer, and fled the country with a doctored passport. But he was unmasked in October 2009 when Czech police called Auckland detectives and gave details of his identity and an arrest warrant on minor charges in connection with the 2003 murder.
Antolik, who has New Zealand residency in that name, was found guilty by a jury in November of a false passport charge and making false statements to immigration officials.
Judge Wade told Antolik in December his penalty was "one of the most difficult sentencing decisions I have ever had to come to". Under normal circumstances, the offences warranted a prison sentence of 18 months to two years' but Antolik's story was an "exceptional case".
David Jones, QC, drew Judge Wade's attention to the section of the Immigration Act that allows the Immigration Minister to deport anyone convicted of holding a visa under a false identity without any appeal or review.
He urged the judge to discharge his client without conviction to prevent this happening.
Judge Wade agreed Antolik had never been a "drain on the New Zealand public", and had made a positive contribution through his kickboxing prowess and business success.
He was convinced that Antolik would still be in danger from corrupt Czech authorities and the man he helped convict of murder if he were deported to the Czech Republic.
"I am satisfied that your initial false applications were as a result of you doing the right thing, not the wrong thing, and furthermore, had you been frank with the authorities when you first came here, it seems plain that you would have been granted a work permit and, ultimately, residence in any event, on your own merits."
In his submissions, Crown prosecutor David Johnstone cited other cases which made it clear that when sentencing, the courts should not interfere with deportation decisions made by Government departments.
But Judge Wade said the Immigration Minister could deport anyone with a false-identity conviction without appeal. A discharge without conviction would not necessarily stop Antolik being deported, he said, but "it will give you a certain chance of being able to argue your case on its merit and not run the risk of your being removed from this country without proper procedure and review".
In the Auckland District Court the Crown did not dispute Antolik's story of fleeing corrupt police officers but said he should have revealed his true identity to New Zealand authorities. The jury agreed and found him guilty on all five charges.
