More information to come on Karel Sroubek case - Jacinda Ardern

Prime Minister Jacinda Ardern says the Government could soon be in a position to open up more about the Karel Sroubek case, but Immigration NZ will have to complete its enquiry first.

Sroubek came to New Zealand in 2003 on a false passport, and built a career as a kickboxer. But he also developed connections with the underworld, which ultimately ended in his jailing in 2015 for importing MDMA.

The case hit headlines when it was reported Immigration Minister Iain Lees-Galloway cancelled Sroubek's automatic deportation order, which would have seen him sent back to the Czech Republic once his prison term was up.

Mr Galloway has refused to explain why, citing privacy and legal reasons. But he now says new information has come to light, and it contradicts what officials had presented to him before, so the case is back under review.

Ms Ardern told The AM Show Mr Lees-Galloway had to rely on the information that had been put in front of him, and the public will soon find out more about what that was.

"Ultimately in these cases the information, as it's always been, the information is put before the Minister, he has absolute discretion and he relies on the file and what's in front of him," she said.

"We'll probably be in a position to talk a bit more about some of the detail behind that [in the] not too distant future, but obviously there's been information in the public domain that's been directly contradictory to some of the information that he had."

Ms Ardern said she wanted to correct assumptions that she had put the blame onto officials at Immigration New Zealand as there were a lot of reasons why information could have been contradictory.

"Hopefully we'll be in a position to talk about it a bit more in the very near future," she said.

Information could come once Immigration NZ has finished looking into the incident. Initially the review was slated to take three weeks, but Ms Ardern has indicated she's not happy with that.

"It's going to be much easier for me to talk about this once we've got to the end point of the extra work that's being done by Immigration," she said.

"I'm hoping of course that it won't be three weeks before we can do that, but sooner. But again, with case files like this you are reliant on that information, people would expect that I think."