The Prime Minister says the issue of human rights was involved in the decision to grant a convicted criminal residency.

Immigration Minister Iain Lees-Galloway has intervened to allow Karel Sroubek to stay in the country.

That is despite the fact he is currently serving five years in jail for importing ecstasy, and he came to New Zealand on a fake passport.

Jacinda Ardern told Mike Hosking privacy concerns mean the Minister can't disclose his reasoning, but it was a tough call made with all the information in front of him.

"There are a lot of things that need to be factored in. For example, human rights is very important."

LISTEN ABOVE AS JACINDA ARDERN SPEAKS TO MIKE HOSKING