From drums to didgeridoos, brass bands to bongos, it was boom or busk in Bondi as hundreds of performers set a new world record.

Within two hours more than 261 performers had crooned, rocked and danced their way into the Guinness World Records, beating the UK-held mark for the world's largest busk.

Among them were school choirs, blues troupes, folk musician and opera singers, the eldest being a 95-year-old violinist and the youngest a four-month-old who stole the show throwing his guitar out of his pram while his father played on.

"We have to be verified by Guinness, but I think we've done it," co-organiser Jay Hemsworth said.

"We needed more than 230."

Bondi FM director Russ Ayres said crowds of more than 100 people built up around performers.

"The youngest registered busker was 4 1/2 years old. She was singing for her father," he added. Performers played for two hours in 100 places as part of the Bondi Winter Magic Festival yesterday afternoon, donating their day's earnings to SoundSchool, which teaches music to disadvantaged children.