Private bus operators along the Chilaw-Colombo route launched a strike on Thursday.
Chillow-Colombo Bus Owners Association Chairman Chaminda Hansa said the strike was in protest of the attack on a bus driver and to demand the authorities to take action against the culprits.
The victim is receiving treatment at the Chilaw General Hospital, he said.
A manager of the Jaffna-Colombo Private Bus Service and a driver along with 40 other persons had attacked the driver, he said.
A complaint was lodged with Maradana police, he said.
All the bus services from Chilaw would join the strike if action were not taken against the culprits, he said.