Australian surf lifesavers lined the shore of Sydney's Bondi Beach and fell silent on Saturday to honour the 15 people shot and killed when gunmen fired into crowds at a Jewish festival by the sea.

Scores of rescuers stood by the water's edge along the entire length of the beach, six days after two assailants allegedly carried out one of the deadliest mass shootings in Australia's history.

Gunman Sajid Akram, 50, was shot and killed by police. His 24-year-old son Naveed survived and remains in hospital under police guard facing charges including terrorism and 15 murders.

Facing the ocean while wearing their red-and-yellow uniforms, the lifeguards observed three minutes of silence.

Some cried or hugged each other at the morning ceremony, with a surf lifesaving helicopter hovering overhead, television images showed.

Volunteer surf lifesavers across the country, who number more than 200,000, were being asked to join the homage in solidarity with those affected by the Bondi attack before starting their morning patrols.

Ocean rescuers wanted to recognise the "tragedy that has unfolded at Bondi while also reflecting on our respect and compassion for the Jewish community targeted by this attack", Bondi's two lifesaving clubs said in a message.

"We pay respects to those who lost their lives, those who risked their lives, those who worked so hard to save lives, and all of us who will never forget."

Lifeguards at Bondi have been widely praised for their courage on the day of the December 14 attack, dragging people to safety, bandaging and resuscitating victims, and pulling panicked swimmers from the waves.

A photo shared widely online showed lifeguard Jackson Doolan running barefoot down the road from a neighbouring beach towards the Bondi shooting, carrying a defibrillator to help victims.

The local mayor described his actions as "remarkable".

On Sunday, Australia will hold a national day of reflection with the theme "light over darkness" marking a week after the attack started with a minute's silence at 6.47pm, or 3.47pm Hong Kong time.

Flags will fly at half-mast, and Australians are being asked to light a candle in their windows to honour the victims and stand by the Jewish community, Prime Minister Anthony Albanese said.

"Sixty seconds carved out from the noise of daily life, dedicated to 15 Australians who should be with us today," he said on Saturday.

"It will be a moment of pause to reflect and affirm that hatred and violence will never define us as Australians."

Federal and state authorities are talking with Jewish community leaders about establishing a permanent memorial at Bondi Beach, as well as holding a national day of mourning in the new year, Albanese said. (AFP)