Tonga coach and former Wallabies star Toutai Kefu was in a critical condition Monday after being stabbed by intruders at his Brisbane home during a "brutal and violent" attack, as the rugby world rallied around him.

The 47-year-old was among four people rushed to hospital after the early hours incident when several youths allegedly broke into the family house.

Detective Superintendent Tony Fleming told reporters that an axe and knife had been recovered, calling it a "brutal and violent" assault.

Kefu underwent surgery for serious wounds to his abdomen, with his wife and children also hurt.

"His (Kefu's) initial condition was described as critical, but expected to survive," Fleming said. "The mother has suffered very, very serious lacerations to her arm and I'm told her wounds are very significant."

Their 21-year-old son sustained "terrible" wounds to his arm and back and a daughter was also injured.

Police said two teenagers had been arrested, with another suspect still at large.

Tonga coach Toutai Kefu has reportedly been stabbed by intruders at his Brisbane home
Tonga coach Toutai Kefu has reportedly been stabbed by intruders at his Brisbane home AFP / MICHAEL BRADLEY

"It is highly likely a burglary that has gone wrong, although I think that understates it," said Fleming. "But I can say we do not believe this was targeted."

Rugby Australia chief Andy Marinos called it "shocking news".

"To the Kefu family -- the Australian Rugby community is here for you," he said, while the Wallabies tweeted: "You got this great man!! All our love and thoughts to you and the entire Kefu family!!."

The All Blacks also offered their support, saying: "Our thoughts are with Toutai Kefu and his family at this time. A warrior on the field and leader off it, we are pulling for you!".

Kefu, 47, was a powerful No.8 who played 60 times for Australia over a seven-year international career, making his debut against South Africa in 1997 in Pretoria and helping the Wallabies win the World Cup two years later.

He was appointed head coach of the Tongan national side in 2016 and steered them through to the 2019 World Cup in Japan. They failed to qualify from their group but gave France a huge scare in a 23-21 loss.

Former All Black great Sonny Bill Williams said his "thoughts and prayers are with my Tongan brother Toutai Kefu & his family" while Samoa head coach Seilala Mapusua urged them to "stay strong."