Police have won an 11th-hour court battle to shut down an anti-lockout law protest expected to be attended by thousands in Sydney on Saturday night.

A deflated director of the organising group, Keep Sydney Open, said the police’s win was a last-minute “ambush”.

“Hats off to them, they did a really great job and they got what they wanted,” Tyson Koh told reporters on Friday.

“Not only can you not enjoy a night out on the weekend but you also can’t have a peaceful protest when you choose to.”

The protest was to be on Darlinghurst Road, Kings Cross from 9pm to midnight with an electronic band playing on the street and speeches about the divisive lockout laws.

Keep Sydney Open had registered its intention on January 9 to hold the rally and was served with the court summons on Thursday evening.

Lawyers on behalf of the Commissioner of Police argued at the NSW Supreme Court that the legal action was out of concern for public safety in a residential area and Keep Sydney Open’s lack of preparation.

Mr Koh admitted under cross-examination he could not say for certain how many people would ultimately attend.

He estimated 5000-7000 based on Facebook responses, but did not deny the opposition’s suggestion that numbers could swell to 15,000.

Mr Koh was quizzed by barrister Paul Coady about KSO’s plans for public safety, alcohol consumption, evacuation plans, crowd control and traffic management.

Defence lawyer Mark Robinson SC said police never raised the need for a “whole stack of professional reports” about contingency plans and crowd control.

“It is not a monster, your honour, it’s just a public rally, that’s all,” he said.

Theoretically, protesters still have the right to gather but Friday’s court ruling gives the police the power to move them on if they see fit.

Given the numbers of protesters expected to flood Darlinghurst Road, the court decision means it’s inevitable police will move protesters on.

Mr Koh said the protest would not go ahead as planned and could not say what an alternative event might look like.

Update: the OCCUPY KINGS CROSS event is taking place ~tomorrow~, get on out there and support! https://t.co/7wloYePNVj #KeepSydneyOpen pic.twitter.com/nlZb8nYBv8

— the AU review (@theAUreview) January 20, 2017

A new Facebook Event for ‘Occupy Kings Cross’ has popped up online hosted by ADM (Australian Dance Music), encouraging everyone hit up venues throughout Kings Cross to get behind the venues, DJs and artists who call the hub home every night and weekend.

The lawsuit was launched the same day as the resignation of NSW Premier Mike Baird, who drove through the lockout laws in 2014.

The laws, which dictate last drinks times for bars, pubs and clubs across Sydney’s key entertainment precincts, have been divisive.

The outgoing premier has lauded their success in reducing street violence and saving lives while others criticise them for ruining Sydney’s night life.