Image shows the NZ mosque shooter, Brenton Harrison Tarrant

New Zealand’s Prime Minister Jacinda Ardern said on Monday that her cabinet has made an in-principle decision to tighten gun ownership in the aftermath of the Christchurch mosques massacre.

“We have made a decision as a cabinet, we are unified,” said Ardern.

The New Zealand prime minister also announced an inquiry into the mass shootings at two mosques in Christchurch on Friday that left 50 people dead.

Ardern said the details are still to be worked out but the changes to the country’s firearms laws will be announced in full within 10 days.

She also said that while the man charged with carrying out the shootings was not a New Zealand citizen, it could not ignore the problem of white supremacy supporters within the country.

A Christchurch gun shop on Monday acknowledged selling guns online to the 28-year-old white supremacist accused of killing 50 people in mosque shootings.

At a news conference, “Gun City” owner David Tipple said the store sold four guns and ammunition to suspect Brenton Harrison Tarrant through a “police-verified online mail-order process”.

Ardern has said the attacker used five guns, two of them semi-automatic, which were purchased with an ordinary gun licence and modified.

It was not clear if any of the firearms Tarrant purchased from Gun City were used in Friday’s shootings.

“We detected nothing extraordinary about this licence holder,” Tipple said, referring to the shooter.

Gun City has been criticised for leaving out a roadside advertising billboard that shows a parent helping children with rifle target practice in the wake of the shootings.

On Monday, Tarrant’s lawyer said his client was not mentally unstable and planned to represent himself in the court.

At his first court appearance, Tarrant didn’t speak but appeared unrepentant, smirking at journalists and flashing an upside down “okay” sign – a symbol associated with white power groups around the world.

The suspect had posted a muddled, 74-page anti-immigrant manifesto online before the attacks and apparently used a helmet-mounted camera to broadcast live video of the slaughter.