"The Parlotones fund-raising performance at Pappas restaurant on Nelson Mandela Square in Sandton has been cancelled due to lead singer Kahn Morbee needing emergency surgery on his vocal cords," spokesman Vuyo Lutseke said in a statement.
"A new date for the children's hospital fundraiser will be announced once rehabilitation has commenced."
The performance was scheduled to take place on August 27.
Lutseke said all tickets that were bought or booked would be fully refundable.
"We also thank all the music lovers that had already brought tickets to the performance," he said.
Morbee's surgery to repair his vocal cords, had also caused the postponement of all the band's other performances and promotional activities.
"We would like to wish Kahn all the best with his surgery and recovery. As our ambassadors, the band has been committed to lending their name to the cause and helping us raise funds towards the building of the hospital," said Lutseke.