The biggest fundamental change to Sydney's late-night bar and club scene in 30 years will go live days before one of the city's biggest annual party nights, police say.
The NSW government's promised 3am last drinks and 1.30am lockouts for CBD and Kings Cross licensed premises comes into effect on Monday morning.
A statewide ban on takeaway alcohol sales after 10pm also comes into effect on Sunday night.
The timing of the introduction means that the first Saturday that police and liquor inspectors will spend enforcing the new laws around central Sydney is also Mardi Gras parade night on March 1.
Hundreds of thousands of spectators are expected to line the inner Sydney parade route to watch 10,000 people march as part of the annual gay and lesbian pride festival.
"Come Friday night we'll have an extra 80 police above what we usually have and then of course on Saturday night, Mardi Gras, it'll be many hundreds of additional police on the street," NSW Police Assistant Commissioner Mark Murdoch told reporters on Friday.
"Mardi Gras will give us a bit of a false sense of what it's going to be like because there will be tens of thousands of extra punters in the city we would not normally have."
But Mr Murdoch expected many Mardi Gras revellers to leave the city shortly after the parade.
Office of Liquor, Gaming and Racing executive director Paul Newson said anyone gearing up for a night out in the Sydney city-Kings Cross entertainment precinct needed to plan for the changes.
"By 1.30am, they need to be in a licensed venue," Mr Newson said.
"If a patron gets ejected or is refused admission, they can't access either that venue or any other venue in the precinct."
Mr Murdoch said police were bracing for a possible drift of locked-out revellers to late-night bars in city fringe suburbs such as Newtown, Pyrmont, Balmain and Surry Hills.
"This is the biggest fundamental change we've seen in 30 years in terms of how we operate late-night trading in the city," he said.
"We're going to have to suck it and see."
Police Minister Mike Gallacher said he was confident the measures, introduced in the wake of a series of high-profile alcohol-fuelled attacks on Sydney streets, would not hit businesses.
"If they are producing a product that is a good product that young people want to go to, they're going to go there," Mr Gallacher said.
There are about 1300 licensed premises within the designated precinct but some are exempt from the new restrictions.
