John Barakat, the former licensee of Kings Cross bar Deja Vu, and Dominic Kaikaty, the venue's former manager, have been handed the toughest sanctions ever imposed on rogue bar operators in NSW for repeated breaches of the Liquor Act, acting NSW Premier Troy Grant said.

Mr Barakat and Mr Kaikaty ran Deja Vu between January 2013 and March 2014, and in that time showed an "extraordinary" contempt for the authorities, Mr Grant said.

In one instance, bar staff had served a 15-year-old and 17-year-old 10 shots of alcohol, six beers and mixed spirits, before the older boy started vomiting inside the venue.

When he collapsed on the footpath outside Deja Vu, he was allegedly kicked by a venue promoter and told to move on.

Mr Kaikaty was convicted of supplying drugs after he was found inside the venue with six small bags of cocaine, Mr Grant said.

The bar had also been involved in "continuous irresponsible promotions" on its Facebook page, including one cartoon that depicted women engaged in apparent illicit drug use inside the toilets.

A photo of Mr Barakat, Mr Kaikaty and others with their middle fingers extended was also posted on the bar's Facebook page with the caption: "F--- You Kings Cross LAC."

Mr Grant said the venue was forced to shut down for 72 hours in March 2014, but the pair continued to show contempt for the authorities, resulting in the life bans.

The Office of Liquor, Gaming and Racing and NSW Police made a special application to the Independent Liquor and Gaming Authority to ban the pair for life.

"Operating a licensed venue carries serious responsibilities to community and patron safety," Mr Grant said.

"The contempt they showed for authorities is extraordinary and as a result of government action the party is now well and truly over for these two."

Deja Vu has since closed, and a new venue that has opened at the location has no association with the former operators of Deja Vu, a spokeperson for the Office of Liquor, Gaming and Racing said.