Fire crews are dealing with the incident which appears to be in an underground area of the transport interchange.
It is not clear whether any buses or passengers have been affected by the blaze.
Video shared on Facebook shows flames leaping from what appears to be a storage area at the rear of the interchange while a fire engine and crews can be seen tackling the blaze as concerned passengers look on through the building's windows.
There are unconfirmed reports that the fire was caused by wooden pallets being set on fire in an arson attack.
More to follow.