'Zookeepers should have used some other type of non-lethal force' - John Key weighs in on gorilla shooting

Prime Minister John Key has weighed in on the death US zoo gorilla Harambe, saying he wouldn't have killed the 17-year-old silverback.

In an interview with More FM today, Mr Key said it was sad the gorilla was killed.

Harambe was shot dead by a special zoo response team on Saturday after a four-year-old boy fell into his enclosure.

The boy, who fell three metres and was dragged by Harambe, was released from hospital earlier this week.

Mr Key told More FM zookeepers should have used some other type of non-lethal force to subdue Harambe.

"I was out looking at some of the police's top-rate stuff yesterday and they've got these rubber bullet-type things, these stunt bullet-type things," he told More FM.

"Apparently they pack an amazing punch, and if you hit it with that surely it'll knock it over or maybe aggravated it.

A CBS 4 News viewer named Dan was the man who gave the Cincinnati Zoo gorilla, killed at the weekend, its name in the late 1990s.

"I understand no one wants their little boy hurt, but it is just so sad they killed it."

Reuters has reported that police were taking a second look at possible criminal charges against the boy's parents.

So far, no-one has been charged.

Since the incident, an animal rights group has filed a federal negligence complaint against the zoo with the US Department of Agriculture.