Eva Bjoerkman munches on a sandwich, chats with colleagues, and then twirls and bounces to the rhythm at "Lunch Beat", a growing movement in Sweden mixing a work break with a bit of disco fever.

"This is so much fun!" the 28-year-old recruitment worker shouts above the pulsating, electronic beat.

"It is just great to get away from the computer, and really fun to go dancing in the middle of the day," she says, nodding to the hundreds around her jerking and jumping to the music, colourful pearls of strobe light gliding across their faces.

Some have come to get out of the office for awhile, others just for the fun of it.

Whatever the reason, the Lunch Beat phenomenon has rapidly swept across Sweden since 28-year-old Molly Raenge, a concept and project developer, came up with the idea in early 2010.

"I love to work and I love to go out dancing, but was getting frustrated that my two passions were not always compatible," she tells AFP.

"So I began thinking: What happens if you combine the two?"

It started off small in May last year, with just 14 people in a garage "somewhere under Stockholm," Raenge says.

She had wanted to create some kind of "urban fight club esthetic," but received immediate positive feedback and realised her creation might grow beyond the confines of a secretive, underground movement.

At a recent event held at Stockholm's Culture House in the heart of the city, more than 300 people cram into a large dark room. Only the thin slivers of daylight peeking through the blackout curtains and the absent odour of stale beer betray the authentic nightclub feel.

The Culture House has become a favourite venue for the happenings that now take place about once a month in Stockholm, but the aim is to hold them in alternate locations. An event planned for January will be held for instance in a museum in the basement of the royal palace.

"I like the idea of our journey from garage to palace," Raenge jokes.

Lunch Beat events have also popped up in about 10 other Swedish towns to date, one has been held in Belgrade and another is planned for Bogota.

"I haven't wanted to copyright the idea, since it came out of this whole 'share' philosophy... I want these to spring up everywhere," Raenge says.

Anyone can arrange a Lunch Beat event as long as they adhere to the manifesto posted on the lunchbeat.org website, which stipulates that everyone must dance, the event must be non-profit and held for exactly one hour at lunchtime during the work week, and food must be provided.

When the doors open at noon, people of all ages and occupations flood in, purchasing their 100-kronor (11 euros, $15 dollars) tickets before making a beeline for a counter covered with baskets of bananas, pitchers of water and plastic cups.

The bananas and water are free, but to get the wrapped lunch patrons need to swap in their entrance ticket. In the beginning salads were offered but lettuce flew on the dance floor so today's meal is a sourdough baguette filled with baked veggies.

Some people hover around tall, round tables to eat and others briefly sit on leather couches lining a far wall, but most people can't wait to get onto the dance floor, chewing and dancing at the same time.

Suit-clad businessmen bounce in time with ballet school students, pensioners and even a few children, as DJ Nadja Chatti pumps out an electrifying house mix.

After about 20 minutes, Bjoern Erik and Tina Oeye, a couple in their 50s, rush to the counter for a drink of water before diving back into the crowd.

"This is such a great concept," Bjoern Erik, a market analysis consultant, says, wiping sweat from his brow.

"We love to dance! Finally we can do so during the day. Otherwise, we're already in bed when the clubs get going," his wife laughs.

Asked whether it bothers him to get all sweaty and then go back to the office, he says: "No, I'll carry it like a badge of honour."

Nearby, Ivar Forstadius, 32, sways gently to the beat, his hand resting protectively on his six-month-old daughter Silvia, snuggled in a Baby Bjoern carrier on his stomach, with giant yellow hearing protector muffs on her ears.

"This is her second Lunch Beat. She loves it!" he shouts, adding that his wife is also grooving in the pulsating crowd.

"It feels natural to come here as a family," he says.

Anders Rasmussen, a tall, blond bank clerk who has opened his suit jacket and is rocking with a colleague, is here for the fourth time.

"I go out a lot in the evenings, but it's different during the day. No one is drunk and you get to go back to work after," he says.

And many like him feel it's important to get out of the office and clear their heads for an hour with something totally different.

"I feel like I work better after this," he says.