Thousands of people gathered in Sydney for a pro-Palestine protest, despite organisers being denied the chance to rally at the Sydney Opera House.

The Palestine Action Group had a request to march to the Opera Houserejected by three judges in a court ruling on Thursday on the grounds of public safety.

This decision came after the NSW Premier Chris Minns and NSW Police initially blocked the move.

Organisers were looking to replicate theAugust protest on the Sydney Harbour Bridge, where around 100,000 people braved the rain to protest against the war in Gaza, which has killed 67,000 people according to Gaza's Health Ministry.

Up to 40,000 were expected to turn out for this week's protest, which has become a regular occurrence on Sundays in Australia's major cities.

The demonstration began at around 1pm at Hyde Park.

There was a heavier security presence than normal, with security checkpoints being set up in and around Hyde Park.

"Our right to protest is paramount in a democratic society," Damian Ridgwell, part of the Palestine Action Group, told reporters after Thursday's court ruling.

Brisbane and Melbourne also held marches.

Protests were also expected in Canberra, Cairns and Coffs Harbour.

Sydney also saw protest of another kind, as a convoy of boats sailed on Sydney Harbour as a demonstration against anti-semitism.