A Sydney shopping centre has reopened to the public for the first time since a mass stabbing in which six people died.

The deadly rampage through Westfield Bondi Junction on Saturday was the earlier of two knife attacks by lone assailants over three days that have traumatised Sydney.

The man who stabbed 18 people in Saturday’s attack, Joel Cauchi, was shot dead by police.

A 16-year-old boy is also in police custody after he allegedly stabbed a Christian bishop and priest during a church service on Monday.

Police allege the boy had a religious or ideological motivation and attacked during the streamed service to cause intimidation.

Meanwhile, Prime Minister Anthony Albanese has praised those who intervened in Saturday’s attack to prevent more deaths, including security guard Muhammad Taha, who was stabbed in the stomach.

Mr Taha is from Pakistan and working in Australia on a temporary visa that is due to expire within weeks.

Albanese said his government would consider giving Mr Taha citizenship, the same reward he had earlier offered French citizen Damien Guerot for his own heroic intervention.

Mr Guerot was nicknamed “Bollard Man” on social media after security camera footage showed the construction worker standing at the top of an escalator on Saturday and menacing attacker Cauchi with a plastic bollard as he approached.

Cauchi fled down the escalator and people on Mr Guerot’s floor were safe.

Mr Guerot’s temporary Australian work visa was due to expire in July until Mr Albanese intervened.

While Mr Guerot had been offered citizenship, he wanted a permanent resident visa, which he would receive on Thursday, Mr Albanese said.

While the Westfield Bondi Junction shopping centre reopened on Thursday, shops will remain closed for what is described as a “community reflection day”.

The businesses in one of Australia’s largest shopping malls will reopen on Friday with higher security.

Police are conducting major investigations into the shopping centre attack, the stabbings at the Christ the Good Shepherd Church and the riot that occurred outside the Orthodox Assyrian service as people sought vengeance over the attack.

The shopping centre attack is not a criminal investigation, but police are gathering evidence to present to a coroner to investigate the circumstances of the deaths.

Five of those killed were women and one was a male security guard.

The investigation into the riot made its first arrest late on Wednesday when police took a 19-year-old man from his Sydney home.

He remained in police custody overnight and will appear in a court on Thursday charged with riot, affray and damaging property during public disorder, a police statement said.

Dozens more suspected rioters are expected to be charged.