The New South Wales Supreme Court has ruled that a protest march against Sydney's lockout laws cannot go ahead in Kings Cross today.

The Keep Sydney Open group applied to police on January 9 for a permit to hold the rally on the corner of Darlinghurst Road and Bayswater road from 9:00pm.

The group has spearheaded the opposition against laws, introduced in 2014, which force licensed venues in the city's CBD and Kings Cross to close their doors at 1:30am and serve last drinks at 3:00am.

A band was scheduled to play to a predicted crowd of between 5,000 and 7,000 people, which could have grown to as large as 15,000 people.

The Commissioner of Police requested and was granted a Supreme Court order prohibiting the event going ahead.

Organisers failed to properly plan event, court told

Police said organisers had failed to adequately plan for the event, alleging there was no security or traffic planning, no event insurance and organisers had failed to show mass evacuation and crowd dispersal plans.

Police also said blockades on local streets would restrict ambulance access to nearby St Vincent's Hospital.

But the barrister for Keep Sydney Open argued police were interfering with freedom of speech and asked the court to reject the police application.

They argued police had not required the group to produce evidence of any of the listed measures relied upon at any time during the permit application process.

In coming to his decision to stop the event going ahead, Judge Geoff Lindsay said he had carefully weighed the rights of freedom of speech and assembly against public safety laws.

Protesters disappointed at outcome

After the hearing Keep Sydney Open spokesman Tyson Koh said he was disappointed with the decision, but the group would comply with the court's order.

"I think this really strikes to the root of why Keep Sydney Open exists and why people are really angry about the lockout laws," Mr Koh said.

"Not only can you not enjoy a night out at the weekend, but you also can't have a peaceful protest when you choose to as well."

The group hopes a change in premier will signal a change in policy, with Liberal Treasurer Gladys Berejiklian touted as the most likely person to replace outgoing Premier Mike Baird.

"We've seen that issues like the lockout laws, have been toxic for the previous Premier and so obviously Gladys [Berejiklin] has a lot of soul searching to do," Mr Koh said.