Immigration Minister Iain Lees-Galloway has announced Czech drug-smuggler Karel Sroubek is liable for deportation when he is released from prison.
Mr Lees-Galloway said some information was not available to him when he made the original decision.
This included new information from Interpol confirming details of his convictions, including that he was present in court when found guilty and that he appealed the verdict to the highest court in the Czech Republic.
"He doesn't have residency now because he's not produced a valid travel document. But this decision of deportation overrides that.
"At the point where he was released on parole or at the end of sentence, INZ would step in and he would be removed from the country."
Mr Lees-Galloway said Sroubek was being removed because he never had the right to hold the visa in the first place.
He had the right to appeal that.
"This was an unusual case," Mr Lees-Galloway said.
Sroubek's release is scheduled for around 2022.
Mr Lees-Galloway said he considered the likelihood that some of Sroubek's claims that he was in danger by Czech officials could have been misleading, but there was one fact that he could not ignore - the fact that Judge Roy Wade had accepted Sroubek's life would be in danger if he did return.
"It is difficult to dismiss such a decision from our judiciary out of hand."
Immigration NZ is conducting a review in the way case files are put together, which should be completed by March.
He said he never considered putting in his resignation, but had apologised to Prime Minister Jacinda Ardern.
Mr Lees-Galloway said he spoke to the PM last night and told her of the processes he would now take. He said Ms Ardern accepted his apology and that his top priority now was to restore public trust and confidence in the process for dealing with these cases.
"All parts of the immigration system must have integrity."
He said he was aware that trust and damage had been done by this case.
"This case has exposed potential limitations.
"I will immediately change my approach to case work, I will now receive the file in advance of meeting with officials and take as long as I need to scrutinise the file before that meeting takes place."
He said it will slow down the process but it was important to get it right.
Sroubek's lawyer, Paul Wicks QC, said his client was disappointed when he told him the news over the phone.
However he said Sroubek planned on appealing the decision through The Immigration and Protection Tribunal and was also weighing up a judicial review.
Watch the press conference here:
Mr Lees-Galloway has been under intense political pressure over his decision not to deport Sroubek.
Sroubek entered New Zealand in 2003 under a false passport and gained residency in the name of Jan Antolik in 2008. This was granted under the sports talent category as he was the world kick-boxing champion at the time.
Last month Mr Lees-Galloway granted Sroubek residency under his real name after what he said was careful consideration of all the information available at the time.
Mr Lees-Galloway subsequently admitted that he took only an hour to decide to let Karel Sroubek stay in New Zealand and did not read his entire case file.
Mr Lees-Galloway launched a review of his decision to grant residency to Sroubek after receiving "new information", which appeared to contradict information he had relied upon to make that decision.
As well as being a world champion kick-boxer, Sroubek has a criminal history both in New Zealand and in the Czech Republic.
In 2016, Sroubek was jailed for five years and nine months for importing 4.9kg of the drug MDMA, with a street value of $375,000.
A parole decision about that sentence said he came to New Zealand after he had been involved in a problem with Czech police, when a man was shot and killed. And it said he was at the time "associating with criminal elements in the Czech Republic".
An Interpol listing online said he was wanted in the Czech Republic for disorderly conduct, damaging of another's property, and attacking a law enforcement officer.
Czech Republic's Justice Ministry said Sroubek was sentenced to four years and six months in prison in the Czech Republic. He is also being sought for further criminal charges.
In 2011 he was found guilty of supplying false information to the Immigration, and of having a false passport. Also that year, he was convicted with being a party to the manufacture of a Class C controlled drug. The latter conviction was quashed on appeal.
In 2009 Sroubek faced charges of kidnapping and aggravated robbery for which he was acquitted.
He was associated with New Zealand's Hell's Angels and had been charged with some gang members for offences, but they were all acquitted at trial.