Immigration Minister Iain Lees-Galloway is standing by his decision to give New Zealand residency to a convicted drug smuggler from the Czech Republic and would do the same again.

Photo: RNZ / Richard Tindiller

Iain Lees-Galloway is under fire from the National Party, which is calling for him to resign.

They want him to be clear with the public about why Jan Antolik, also known as Karel Sroubek is allowed to stay.

Mr Sroubek had previously been granted residency status, but under a false identity.

Two years ago he was jailed for more than five years for importing nearly 5kg of MDMA, commonly known as Ecstasy, with a street value of $375,000

Mr Lees-Galloway said he would make the same decision again based on the information he had.

"Decisions can be incredibly difficult, this was right up there, probably the most difficult decision I've had to make so far.

"But as I say, I've taken the opportunity to review that decision to assure myself I made a reasonable decision and I stand by it,'' he said.

National Party justice spokesman Mark Mitchell said the government's decision made a mockery of the system.

Mr Mitchell said he was "very serious" about considering going to the Czech Republic to get to the bottom of Mr Sroubek's past.

Mr Lees-Galloway yesterday released a letter outlining a number of conditions Mr Sroubek must abide by in order to stay in New Zealand.

They include not reoffending, not using a fraudulent identity or misleading a government agency within the next five years.