The Government is ruling out a return to registering guns.

The Greens are advocating a firearms registration be set up following the shooting of two police officers in Christchurch. The party says registration is a way of knowing where weapons are.

However, Police Minister Judith Collins says police have told her the horse has long since bolted on that idea after the practice was done away with in the 1980s. She says in places where there has been an attempt to reintroduce registration, such as in Australia, it has been a minefield of disasters in terms of trying to track firearms.

Ms Collins says it would use a huge amount of police resources better used to keep the public safe.