The man who stabbed six people to death in a horror attack at a Sydney shopping centre has been identified.

Joel Cauchi, 40, moved to Sydney from Queensland last month, NSW Police confirmed on Sunday.

Assistant Commissioner Anthony Cooke said the man was known to authorities in his home state. 

“We are and have spoken with his family and we will continue to do so and they are cooperating with us,” he said. 

“We have received no evidence that we have recovered, no intelligence that we have gathered that would suggest that this was driven by any particular motivation, ideology or otherwise.

“We know that the offender in the matter suffered from mental health.” 

Cauchi was shot dead by a lone female police officer at the scene.

The mass stabbing on Saturday afternoon at the Westfield centre at Bondi Junction has prompted a massive police investigation.

Six people, five women and one man, were killed in the attack and several others were injured.

Two of the six victims were from overseas and have no family in Australia, Mr Cooke said.

The number of people in hospital rose by three overnight, taking the total to 12.

A nine-month-old baby was among those stabbed and underwent surgery on Saturday night, NSW Police Commissioner Karen Webb told reporters on Saturday.

NSW Healath Minister Ryan Park said on Sunday the child remained in a critical condition in ICU at the Children’s Hospital in Randwick. 

The child’s mother was one of those who died, passing her baby onto strangers and begging them to help before she lost conciousness, Sydney’s Daily Telegraph reported. 

Prime Minister Anthony Albanese said the senior female police officer who shot the assailant was “certainly a hero” who no doubt saved lives.

Ms Webb said on Saturday night police were confident there was no ongoing threat and the attacker acted alone.

The shopping centre is closed and will be an active crime scene for days.

Police are not ruling anything out as they begin a “lengthy and precise” investigation but there was no indication of “any motive or ideology” in the early stages of the investigation, NSW Police assistant commissioner Tony Cooke told reporters.

NSW Premier Chris Minns said it was a truly shocking day in the state’s history.

“I can understand that people will be grieving and very angry for the next few days,” Mr Minns told Sydney radio 2GB on Saturday from Japan’s Tokyo Airport, where he was waiting for a flight home.

“It’s literally everyone’s worst nightmare … a wicked and a violent crime,” he said.

Acting NSW Premier Penny Sharpe told ABC News a crisis cabinet had been convened following the tragedy and Mr Minns had joined the meeting by phone from the airport in Tokyo.

Mr Albanese said the attack was a horrific act of violence indiscriminately targeting innocent people, and praised the actions of the police inspector who responded alone as hundreds of shoppers fled the scene.

“She is certainly a hero, there is no doubt she saved lives through her actions,” Mr Albanese said on Saturday.

Federal Opposition leader Peter Dutton said there was heroism amongst the horror.

“We thank everyday Australians who helped each other get to safety and those who provided comfort to others in distress,” he said on social media.

King Charles said in a statement overnight that he and Queen Camilla were “utterly shocked and horrified to hear of the tragic stabbing incident in Bondi”.

The royal couple praised the “bravery of the first responders and emergency services”.

Pope Francis also expressed his sadness at the “senseless tragedy” and offered his “spiritual closeness” to all those affected.

Ms Webb said the inspector was doing well under the circumstances and will be interviewed on Sunday.

“She showed enormous courage and bravery,” Ms Webb said, adding other responding police, civilians and staff at the centre had too.

“It was an awful situation … but it could have been much worse,” she said.