New Zealand mosque gunman Brenton Tarrant was sentenced to life in prison without parole Thursday for the massacre of 51 Muslim worshippers, with a judge calling him "wicked" and "inhuman".

Judge Cameron Mander said that behind Tarrant's "warped" ideology was a "base hatred" that led him to attack defenceless men, women and children last year in New Zealand's worst terror attack.

Brenton Tarrant, a 29-year-old Australian, admitted to 51 charges of murder, 40 counts of attempted murder and one charge of committing a terrorist act during the 2019 shooting rampage at two Christchurch mosques which he livestreamed on Facebook.

High Court Judge Cameron Mander said in Christchurch on Thursday that a finite term would not be sufficient. “Your crimes, however, are so wicked that even if you are detained until you die it will not exhaust the requirements of punishment and denunciation,” said Mander in handing down the sentence. “As far as I can discern, you are empty of any empathy for your victims,” he said.

"It is incumbent on the court to respond in a way that decisively rejects such vicious malevolence," Mander said as he announced a sentence unprecedented in New Zealand legal history.

The judge said Tarrant had failed in his aim of promoting right-wing extremism as he gunned down victims in cold blood but the New Zealand Muslim community had still paid a terrible price.

"It was brutal and beyond callous. Your actions were inhuman," the judge said.

Tarrant sparked global revulsion on March 15, 2019 when he rampaged through two Christchurch mosques for 20 minutes during Friday prayers.

The atrocity shocked New Zealand and prompted Prime Minister Jacinda Ardern to immediately tighten gun laws and pressure social media giants to curb online extremism.

AFP