According to reports from the Selayang Fire and Rescue Department, there were no fatalities, but 14 people were injured, including the driver, from the incident which occurred at 3.50pm.
Authorities rushed to the scene and the injured were taken to the nearest hospital by ambulances and the Civil Service Department.
When Fire and Rescue arrived all the injured victims had already been guided out of the bus.
Meanwhile traffic was reported to be at a crawl from the Genting Sempah tunnel towards the Gombak toll plaza.
As at 5pm, Star Traffic said vehicles along the stretch were in a 9km crawl.
Road users are advised to use alternative routes.