A magistrate has ruled a pro-Palestinian march should not take place on a major bridge over fears it will pose a "significant risk to public safety".
Rally organisers have indicated they may defy the court order and go ahead with the protest on Brisbane's Story Bridge on Sunday.
Police launched legal action to stop thousands of people marching on Queensland's landmark six-lane bridge as part of a national day of action.
Chief ,agistrate Janelle Brassington on Thursday ruled against it taking place, removing legal protections for participants and ensuring police have the power to charge or arrest protesters if they obstruct traffic.
Brassington said rally organisers had good intentions but their proposal to cross the bridge could easily get out of control.
Up to 10,000 people were expected to attend the Brisbane rally as part of the nationwide day of action billed as the largest pro-Palestinian demonstration in Australia's history.
"Because of the features of the venue chosen there is a significant risk to public safety," Brassington said.
"It will inhibit access to major hospitals in Brisbane and to fire crews."
The march aimed to mirror a recent demonstration across Sydney's Harbour Bridge. Source: AAP / FLAVIO BRANCALEONE/AAPIMAGE
Justice for Palestine Magan-djin did not consent to the alternative route across Victoria Bridge, so Brassington was unable to make an order for that plan to be an authorised protest.
Rally organiser Remah Naji said the march would still go ahead at its planned starting point in a nearby park but was yet to decide on whether to cross the Story Bridge.
"We are considering our options … we are going to make a decision publicly over the next couple of days," she said.
Justice for Palestine rally organisers had earlier indicated they would defy any court order and go ahead with the bridge protest to highlight the humanitarian crisis in Gaza.
"Plan B is to go ahead. We plan to march across the Story Bridge on the 24th of August," Naji told Nine Network's Today Show.
Queensland Police's senior lawyer Marshall Bostock made the application to Brisbane Magistrates Court seeking to have the protest declared unauthorised.
"If there were anti-social behaviour on the bridge during the course of the procession, (senior police leadership) would not be able to send police in to adequately respond," Bostock said.
Queensland Police assistant commissioner Rhys Wildman said there was insufficient fencing to stop protesters climbing from the bridge's road lanes to its footpaths, which were unsafe.
Justice for Palestine Magan-djin's barrister Angus Scott told Brassington it was not reasonable or necessary for public safety fears to block the march.
"It's not enough to point to inconvenience, disruption or the fact that a sporting game is in the nearby vicinity," he said.
Police and Brisbane rally organisers attempted mediation earlier this week without success.
The march aimed to mirror a recent demonstration across Sydney's Harbour Bridge in which nearly 100,000 people attended in a sea of ponchos amid wet weather.
NSW Premier Chris Minns on Thursday said he would consider introducing legislation to stop the Harbour Bridge being used for protests.
"I'm not ruling it out," he said.
The planned Brisbane protest was supported by civil society groups who said the court action was a waste of taxpayer money.
Queensland Police Minister Dan Purdie urged protesters to respect the court order.
"If protesters defy the decision ... it will not only put people at risk, it will also take hundreds of police away from responding to crime," he said.
