Five Norwegian tourists would face charges over the shooting of protected kereru while in New Zealand in January, if they decide to return to the country.

The men caused outrage both here and in Norway after posting a video of their trip on YouTube, including a clip where one of the men used a high-powered rifle to shoot a native kereru pigeon.

The video showed a man holding two dead kereru and also had a clip showing a paradise duck being shot illegally with a rifle.

Conservation Minister Kate Wilkinson said the Department of Conservation (DOC) had completed its investigation into the hunters and found two paradise ducks had been shot out of season during a four-day hunt near Franz Josef.

"I have received an emailed apology from the five men, and while I accept they now regret what they have done, I don't consider their excuses to be credible," Ms Wilkinson said today.

"The callous disregard these men showed for our native wildlife was outrageous and New Zealanders were justifiably angered by the footage they released."

The men had obtained hunting permits for the Canterbury and Otago conservancies, but did not have permits to hunt on the West Coast, where the offending occurred.

Ms Wilkinson said the District Court could action warrants for their arrest if the men returned here, but it was likely the charges would deter them from doing so.

The hunters will have charges laid against them under the Wildlife Act 1953 and Conservation Act 1987.

The most serious offences carry penalties of 12 months' imprisonment or a fine of up to $100,000.

A DOC spokesman last month said it was up to the Norwegian National Authority for Investigation and Prosecution of Economic and Environmental Crime to decide whether action would be taken against the men in their own country.