The victims of Australia's worst mass shooting in more than three decades are starting to be discharged from hospital

Fifteen people were killed and 42 injured on Sunday - when a father and son duo opened fire on Hanukkah celebrations at Bondi Beach.

A 50-year-old attacker is dead - and his co-attacker 24-year-old son is in hospital in custody.

Six hospitalised victims remain in a critical condition - and four are stable but critical.

Health Minister Ryan Park told Sky News injuries include shotgun wounds to the head and upper body.

He says some people who have had surgery will need more down the track.