New Zealand’s parliament on Wednesday voted almost unanimously to ban “military-style” semi-automatic weapons less than a month after 50 people were killed in mass shootings at a pair of mosques in the city of Christchurch.

The ban, which applies to semi-automatic rifles and shotguns capable of holding more than five rounds, was made permanent Wednesday after being unilaterally implemented by prime minister Jacinda Ardern just six days after the mosque shootings to prevent stockpiling.

“We are ultimately here because 50 people died, and they do not have a voice,” Ardern told parliament Wednesday. “We in this house are their voice, and today, we have used that voice wisely.”

Citizens in possession of banned guns will be granted a six-month buyback period, after which they will be subject to five years in prison if they remain in possession of prohibited weapons. The law provides exemptions for pest control professionals and licensed antique gun collectors.

Ardern received praise for her decisiveness from New Zealand’s center-right party Wednesday but David Seymour of the libertarian ACT party, who cast the lone nay vote, criticized the speed with which the new legislation was passed.

“It is not an attempt to improve public safety, it is an exercise in political theater,” he said.

Ardern had previously defended the ambitious timeline, which was dramatically shorter than the typical six-month period required to pass new legislation in New Zealand.

“My question here is simple: you either believe that in New Zealand these weapons have a place or you do not. And if you do not, you should be able to agree that we can move swiftly,” she said. “My view is that an argument about process is an argument to do nothing.”