Sinead Ellis limbers up side stage at Belfast's Waterfront Hall amid a frenzy of toe-pointing and heel-clicking dancers. The Birmingham girl came third last year in the 15-16 category in the World Irish Dancing Championships and is hoping to improve. "Winning is my dream," she says, smoothing her pink dress, checking her number (66) is secure. She has more than 100 entrants to beat. "I'll be happy if I dance my best and don't fall over," she adds.

There are 3,500 competitors and some 10,000 spectators (even at this level, mammies and daddies still shed tears of pride as their offspring bounce around the stage). And during the official opening on Good Friday - the competition closes tomorrow - the amazingly agile 95-year-old President of the Commission, Tomas O Fearrcheallaigh, kicked off proceedings by encouraging everyone to make a sign of the cross. Meanwhile, this 30th world championships, Oireachtas 2000, is being covered by a TV station set up for the event - Rince TV is broadcast around the venue and into local hotels.

It's come a long way - further lately with sponsorship from Riverdance The Show and Michael Flatley.

This season, hair is Dolly Parton blonde with synthetic Shirley Temple curls. The wigs favoured by most female competitors would not look out of place on a poodle and can cost anything up to £100. Hairpieces are adorned with crown-like hair-bands, the sort Wonder Woman used to wear. Or bejewelled tiaras. Or both.

Makeup is liberally applied, bright blue being a favourite on eyelids, especially for younger competitors. The dresses are lime green, pink, yellow and orange and are fashioned from raw silk, velvet or gaberdine. Thousands of tiny sequins are sewn into the costume while underneath the dress, satin underwear is made from the same material as the lining. Finally, legs are coated in fake tan, to contrast with the brilliant white of the socks.

All in all, the current incarnation of the traditional Irish dancer, Millennium Irish Colleen, bears an uncanny resemblance to that other icon of modern womanhood - Barbie. And although Millennium Irish Colleen was asked to tone it down a couple of years ago after some outfits became overly flimsy, there seem to be no limits on tackiness.

But out of costume, it becomes clear these trappings mask an unexpectedly lean, modern animal. When waiting to perform, the lithe dancers in the Waterfront Hall are like athletes warming up for the track. They wear shorts and T-shirts, they stretch, they jog on the spot. Their bodies are finely toned and have the glow of those who have reached enviable levels of fitness. In their everyday clothes, these are fashionable young women. They wear skin-tight capri pants, handkerchief tops, cropped leather jackets, shiny hair-grips. Everything about them says modern woman. Then they don sequinned dancing gear that screams spoilt little girleen.

Not as much can be said about the get-up of the male dancers. Like their female counterparts they are supremely talented but unlike them the clothes do not make the mannequin. In fact, now that kilts have been largely abandoned, the boys look more like snooker players in their black trousers, coloured shirts and ties. Outside, a group of boys from the US (Americans make up 50 per cent of the world's Irish dancing community) are enjoying the sunshine. Conor McKee from Wisconsin says the contest was fun but that some of the competitors are - "What's the word? Cocky."

"They keep away from you because they think they are better than you," he says. His friends like being so close to so many attractive girls but aren't so keen on some aspects: "I think it's sick that the girls have to put on so much makeup and wear fake hair . . . they end up looking just like everyone else," says one.

Patricia Brady-Mullins, chairwoman of the Oireachtas Committee, says there are no rules that stipulate curls or anything else: "Dresses can be as simple or as elaborate as the individual wishes," she says. "At high level, competition dancers can be competing every weekend and curling can ruin the hair so wigs have been popular for the past two years. There is an element of theatre in the whole thing and competitors have to take things such as stage lighting into account."

Most of the female competitors milling around the Waterfront say they enjoy the dressing up part as much as the dancing itself, although some of those sporting plastic rollers admit they would prefer to dance with their hair straight. One girl says it sometimes goes too far: "Some girls go completely over the top," she remarks as she waits to see if she will get through to the second round of her competition. "It gets worse and worse all the time." Minutes later she finds out she has not been called back. "Ah, that's the way it goes," she says. "It does annoy you a bit, you have worked so hard for months and you think, I was better than some of those. Or the adjudicator was blind as a bat. I'm disappointed but I'm not going to cry about it."

Others are less restrained. Given the intense training that goes into qualifying for the World Championships, tears of both defeat and victory are par for the course. Like ballet dancers these men, women, boys and girls regularly endure bleeding toes and blisters, even broken bones. The dancing at the event from jig to reel to hornpipe is spectacular. As organisers are at pains to point out, it's a phenomenon that could not exist without the network of Irish dancing teachers, supportive parents and this annual competition - the fruits of which went unnoticed by wider audiences before that interval performance at the 1994 Eurovision (in which many former champions took part). Now, worldwide interest in Irish dancing is at an all-time high, with classes being given from Kerry to Kenya.

And perhaps getting bogged down in wardrobe details is missing the point. The atmosphere in the Waterfront Hall this week is quite unique for a world competition. Most dancers are friends as well as competitors. Champions are cheered at the award presentations, but so are those who were never going to reach the winners' podium. At the end of each presentation a loudly enthusiastic hip, hip, hooray from an audience of nearly 2,000 brings everyone back to the parish halls where it all began. And when it is announced that Sinead Ellis from Birmingham has come second in the world, she grins and runs through the hall to hug the girl who has won.