MELBOURNE (AFP) - Australian Open organisers say they are prepared for crowd trouble at this week's season-opening Grand Slam after ugly scenes marred the previous two tournaments. Police numbers have been boosted in the wake of the problems experienced in 2007 and 2008 and officers will be issued with containers of capsicum foam to target any troublemakers in the crowd. Tournament director Craig Tiley said security would adopt a zero-tolerance approach to unruly spectators in a bid to avoid a repeat of the scenes that have tarnished the Open's reputation as the "Happy Slam". "We have full faith in the security team, they're very well trained and prepared for anything that may occur," Tiley said. The crowd problems, unheard of at any of the other tennis Grand Slams, have been an unwelcome distraction for Australian Open organisers in recent years. Ethnic violence erupted on the opening day of the 2007 tournament when Serbian and Croatian fans, wearing the national colors of the bitter Balkan rivals, attacked each other with flagpoles, bottles and boots.Then last year, police used pepper spray to subdue rowdy elements of the crowd watching a match between Konstantinos Economidis of Greece and Chile's Fernando Gonzales.The unprecedented used of the debilitating spray came after police said they were physically threatened by members of the crowd who were engaging "offensive chanting". Police denied they over-reacted after crowd members not involved in the trouble claimed the spray drifted into their faces but officers have this year been issued with the more accurate capsicum foam canisters. Tiley said the crowd problems were caused by a tiny minority and Australian Open organisers wanted to make it clear that loutish behaviour would not be tolerated. "The unfortunate thing is that of the 605,000 fans that came to the tennis last year there were 10 unruly fans," he said. "We have zero tolerance to anyone who comes on site with the specific objevctive of disrupting the enjoyment of other fans. "If they are going to be disruptive, they're going to be immediately ejected. That's the strong message that we're sending out publicly and I think everyone's got that." Police superintendent John Cooke said there would be more police and security officers at the tournament with the power to issue on-the-spot fines, eject fans and ban them from the tournament for 24 hours. "People that misbehave should understand there are consequences and it's most likely they will find themselves outside the arena with a 227 dollar (140 US) ticket in their hand," he said. Tiley said passionate fans and a family atmosphere were major reasons why players rated the Australian Open their favourite Grand Slam."It's very important that we continue our reputation as the 'players' slam' we are known as the players' favourite place to play," he said. Organisers have the power to ban known troublemakers from the tournament but Melbourne's Herald Sun newspaper reported this week that the three men charged over last year's incident were free to attend if they chose.One of the men, Melbourne resident Chris Vlahogiannis, refused to say whether he would make it to Melbourne Park this year."What's it to you, mate?" he told the newspaper. "Why is it any of your business? You can go f- yourself."