(CNN) New Zealand Prime Minister Jacinda Ardern said she does "not understand" why the United States has not passed stronger gun laws in the aftermath of mass shooting events.

Ahead of a summit on online extremism, Ardern was responding to a question by CNN's Christiane Amanpour asking whether countries can learn from New Zealand.

Ardern announced a ban on military-style semiautomatic weapons, assault rifles and high-capacity magazines only days after the March 15 mass shootings on two mosques in Christchurch, which claimed 51 lives.

The Prime Minister said guns have a "practical purpose" in New Zealand but "that does not mean you need access to military-style semiautomatic weapons and assault rifles."

"Australia experienced a massacre and changed their laws. New Zealand had its experience and changed its laws. To be honest, I do not understand the United States," she said.

Read More