Owners of high-velocity air rifles must have a firearms licence from Friday.
The change applies to pre-charged pneumatic air rifles but not to older-style spring-powered airguns or air guns powered by CO2 cartridges, BB guns or paintball guns.
Police Minister Judith Collins says the change means violent criminals can no longer walk in off the street and buy a class of airgun that can have similar power to a firearm.
Owners of air rifles affected by the change have three months to obtain a firearms licence or dispose of the weapon.
Opponents of the new regulations still say the rules will do nothing to stop such weapons getting into the hands of criminals.
The Government acted after the killing of police sergeant Don Wilkinson in 2008 and another man this year.
The change was made through an Order in Council.
The Sporting Shooters Association says the changes are nonsensical. Association president Lech Beltowski says passing laws does not fix problems and those determined to have the guns will still get hold of them.
Mr Wilkinson's mother, Beverly Lawrie, also does not think the changes will achieve much.