Drug-dealing Czech kickboxer Karel Sroubek has been denied parole.

The Parole Board has just revealed its decision after a hearing today.

Sroubek came to New Zealand in 2003 on a false passport in the name of Jan Antolik.

He was found guilty in a 2011 jury trial of using a false passport and lying to immigration officials, but was discharged without conviction by the trial judge, who believed his evidence.

The representative kickboxer claimed he had to flee his home in the Czech Republic in fear of corrupt police officers and a criminal after witnessing a murder.

Four years later, he was jailed for five years and nine months for bringing a drug used to make Ecstasy into the country hidden among legitimate goods.

He is due to finish his sentence in early 2022 and will come back before the board in November.

When he previously appeared before the Parole Board in September last year, Sroubek was deemed an undue risk to the public based on factors including that he attempted to import drugs into New Zealand from the Czech Republic, his association with criminals in the Czech Republic and his association with the Hells Angels in New Zealand.

His case sparked a political firestorm that burned Immigration Minister Iain Lees-Galloway because of his initial decision to grant Sroubek residency.

A review was ordered in the wake of Lees-Galloway's decision to grant residency despite a conviction for drug-smuggling and an admission that he used a false identity to gain a resident visa.

Lees-Galloway was roundly criticised in 2018 for not reading all of Sroubek's file and making his decision in less than an hour.

Lees-Galloway revisited the case after it emerged that Sroubek may have travelled back to the Czech Republic, and eventually issued a new deportation notice to Sroubek.

The Heron review found that the INZ processes were adequate but could be improved.

It said that Ministers applying absolute discretion may have limited time and did not usually receive free and frank advice on deportation cases - though Ministers were also free to take more time and seek further information.

"It is obvious to state that a process which allows a Minister to make a quick decision on a complex case with as little as an oral briefing and no advice is fraught with risk," the review said.

The risk could be mitigated if more decision-making was delegated to experienced experts, which would keep the Minister "above the fray".