Workers evacuated in Sydney CBD fire

Workers have been evacuated from a building in Sydney's CBD after a fire sparked by a computer.

Six fire crews were sent to Kent Street as smoke filled the building, forcing the evacuation of 50 workers about midday on Sunday, a Fire and Rescue NSW spokesman said.

The fire has been extinguished but Sussex Street remains closed in both directions and buses have been diverted.

The building was significantly damaged in the blaze, police say.