A Turkish man has become the 51st victim of the Christchurch terror attack after dying last night following surgery.

The man, 46, was shot in the back and leg when a white supremacist gunman entered the Al Noor Mosque during Friday prayers on March 15. He had been in a critical condition in Christchurch Hospital ever since, and died overnight.

The father-of-two was one of three Turkish citizens injured in the attacks.

His mother and father flew from Turkey following the attacks. They are believed to be at the hospital where he died, alongside his wife.

He died following surgery last night, a Turkish Consulate spokesman told the Herald this morning.

"We don't have a lot of information," he said, as the matter was in the hands of Christchurch authorities. But he said the shooting victim "passed over because of the operation last night".

The consulate had sent a team to Christchurch to support his family and help them prepare the body for repatriation to Turkey, he said.

Turkey's foreign minister announced the death overnight on Twitter, and it was confirmed by New Zealand police this morning.

"Unfortunately, we have lost our citizen ... who was seriously wounded in the treacherous terrorist attack in Christchurch, New Zealand," Mevlut Cavusoglu posted.

Police issued a statement saying: "Police wish to extend their condolences to the man's family and loved ones."

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Prime Minister Jacinda Ardern also expressed her "heartfelt condolences" to the man's family, friends and community.

"This sad news will be felt across Turkey, as well as New Zealand," she said in a statement.

"This man has been in intensive care since the attack. We have all been hoping for the best. However, he has now succumbed to the injuries sustained in the shooting at the Al Noor Mosque.

"I want to acknowledge all the medical staff who have cared for the 49 men, women, and children who were shot and wounded in the attack and taken to hospital.

"This is only the second victim to die while in hospital - the first was unable to be resuscitated on arrival on March 15. This is a testament to the extraordinary work put in by the medical staff at Christchurch, Burwood and Starship Hospitals in the aftermath of the shooting to save lives."

Nine people who were shot in the terror attack still remain in hospital, she said. All are in a stable condition.

"As a country, we continue to send our hope for their speedy recovery," Ardern said.

The man's brother reportedly told Turkish state-run Anadolu Agency that he had been taken to surgery on Thursday, but he could not be saved.

"He had surgery today, they couldn't stop the bleeding so we lost him," the brother was reported as saying.

"We were happy because we thought it was going well, he had been battling for 50 days."

Turkish President Recep Tayyip Erdogan had strongly condemned the Christchurch attack and showed clips of a video taken by the gunman at election campaigns to denounce hatred against Islam.

Last night's death raises the death toll from the double mosque shooting to 51. Around 50 people were injured in the attack on two mosques during Friday prayers on March 15.