JAKARTA - An Indonesian artist and his toddler son who were shot during the mosque attacks in Christchurch, New Zealand on Friday (March 15) sustained several gunshot wounds to their bodies and limbs.

Both are now in stable condition and recovering at Christchurch Hospital, said Mr Hendra Yaspita, the older brother of Mr Zulfirmansyah.

"He was shot many times, his lung was punctured," Mr Hendra told reporters from his home in Lapai village in Padang, the provincial capital of West Sumatra, on Friday night.

When asked about the toddler, he said: "Thank God, he is conscious, he was shot on his hand and leg."

The shootings killed at least 49 people at the Al Noor and Linwood mosques in Christchurch, a city located on the east coast of New Zealand with about 400,000 residents.

Besides Indonesians, citizens of Bangladesh and Malaysia were also caught in the shootings, which saw several dozens of people seriously injured.

New Zealand Prime Minister Jacinda Ardern said on Friday that four people with extremist views are in police custody in connection with the attacks, adding that her country is now on its highest security threat level.

Mr Hendra said his 40-year-old brother and his two and a half-year-old son were attending Friday prayers at the Al Noor mosque when the lone gunman struck.

"We had received information at 1pm... about him in our family WhatsApp group," he added. "I immediately contacted his wife and managed to talk to her, he was unconscious but his condition is stable."

Mr Zulfirmansyah and his family were in Christchurch where he was trying to make it as an artist. Mr Hendra said he has yet to tell their parents about his brother and nephew.

Earlier reports had indicated that a handful of other Indonesians who were also at the mosques had yet to be accounted for.

President Joko Widodo, speaking to reporters during a visit to Sibolga, North Sumatra, said officials from the Foreign Ministry's citizen protection unit are on their way to Christchurch to assist the victims.

"Whoever the perpetrators are, we condemn this violent act," said Mr Joko, who also asked Indonesians in New Zealand to "please be careful and be cautious".