Melbourne's nightclub industry might consider banning energy drinks in its bid to persuade the State Government to overturn the introduction of 2am lock-outs next month.

But other nightclub owners have vowed to fight for their right to party without concessions, and favour a plan to flout the Government's proposed licensing change that will apply to 500 inner-city venues.

A meeting of more than 300 nightclub owners and promoters yesterday voted to establish a fighting fund and an industry association to oppose the plan, amid claims that the lock-out threatened Melbourne's international reputation.

The owners will challenge the lock-out in the Victorian Civil and Administrative Tribunal, and are considering a class action.

Co-owner of Prahran's One-Six-One nightclub, Andrew Sumpter, said the 2am lock-out, after which clubs would not be able to admit new customers, would force thousands of patrons on to the street without adequate police, taxis or public transport.

"This lock-out provision will also give birth to thousands of new Corey Worthingtons," Mr Sumpter said. "There is nothing stopping young people buying a slab of beer at a 24-hour bottleshop and then going to a park or a private party. You watch what happens at 2am - it's going to be mayhem."

The owner of Fitzroy bar Cape Lounge, Alan Evers-Buckland, said that not selling energy drinks would help curb a 17% jump in city assaults last financial year. "It's important that we take voluntary measures to demonstrate to the Government that our industry is serious about reducing violence," Mr Evers-Buckland said.

He said there was a direct link between violence and energy drinks mixed with potent spirits, such as Jagermeister.

Andrew Ranger, organiser of the protest group Melbourne Locked Out, said his internet site had received more than 100,000 hits over the past two weeks. He expects more than 20,000 angry clubbers to attend a rally in the Treasury Gardens on May 30.

The lock-out would "damage Melbourne's reputation as the nation's restaurant and entertainment capital", Mr Ranger said. "If you're out late, you'll no longer have the option of a dance, or a quiet glass of wine or music, because these laws will stop you from switching venues."

He urged the Government to talk to owners and operators before introducing the three-month trial lock-out on June 3.