Accused gunman's family apologise to New Zealand after Christchurch attacks - 'We are all gobsmacked'

Relatives of an Australian man charged with murdering Muslim worshippers at two mosques in Christchurch say they are devastated and sorry for the families of those allegedly killed by one of their own.

"We are so sorry for the families over there, for the dead and the injured," Brenton Tarrant's uncle Terry Fitzgerald told Nine News in the New South Wales city of Grafton tonight.

Tarrant's 81-year-old grandmother, Marie Fitzgerald, said the family was devastated that it was their own blood who had been charged with murdering Muslims at mosques in Christchurch.

"We are all gobsmacked, we don't know what to think. It's just so much of everything to take in that somebody in our family would do anything like this."

Tarrant spent most of his time on computer games during his high school days rather than chasing girls, his grandmother said.

Tarrant had returned to his home town 12 months ago for his sister's birthday.

His sister and mother have been put under police protection after Friday's attack.

Tarrant will be prosecuted in New Zealand over the Christchurch mosque attacks that killed 50 people. He faces one charge of murder but police have indicated more charges will follow.

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    The pair spoke to Channel Nine after Tarrant was charged with murder over the mosque shootings. Source: Nine