The New South Wales (NSW) premier has strongly rejected criticism of the police response to the attack on a Jewish festival at Bondi Beach, saying officers acted with "bravery and integrity".

Some witnesses have suggested police were too slow to disarm the two gunmen, who killed 15 people and injured dozens at an event celebrating Hanukkah at Australia's best known beach.

"There are two officers in critical care... at the moment," Chris Minns said after sustained questioning from reporters. "They weren't shot in the back as they were running away. They were shot in the front."

There have also been questions about whether adequate security was provided before the shooting took place.

"They shoot, shoot, change magazine and just shoot," one witness, Shmulik Scuri, told reporters the day of the assault, adding he thought officers "froze".