The man who fatally stabbed six people on Saturday (April 13) had mental health issues in the past and there was no indication ideology was a motive in the attack in one of the city's busiest malls, police said on Sunday.

At the floral memorial, federal member of parliament Allegra Spender said that "the one thing I take from this is there was one person trying to harm and there were hundreds of people out there doing their best to keep each other safe and protect each other."

The attacker, identified by police as Joel Cauchi, was known to police in the neighboring state of Queensland, and police have spoken to his family after Saturday's attack, police added.