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 later crucial in convicting the suspect, 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 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".
In his submissions to the court, defence lawyer 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 that 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 back 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 person making the decision about Antolik's immigration status should be careful and he was not "100 per cent sure" that would happen, as 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".
He told Antolik he would be discharged without conviction if he did his community work by February 28.
Antolik pleaded not guilty in the Auckland District Court but at trial in November admitted using a false identity to come to New Zealand.
His defence was that he had a "reasonable excuse" to give a false name as he had fled his homeland in fear of corrupt police officers and a criminal.
The Crown did not dispute his story but said Antolik should have revealed his identity to New Zealand authorities. The jury agreed and found him guilty on all five charges.
An Immigration spokeswoman said the department was "currently investigating the case of Jan Antolik/Karel Sroubek's liability for deportation".
Bill Hodge, associate professor of law at Auckland University, said that in his experience the ruling was unique in an immigration context, but quite common in criminal cases where a judge believed a conviction outweighed the seriousness of the offence.
