Police were called at 10.31am by members of the public concerned for the safety of a woman on the bridge near to Sainburys’ in Pontypridd.
The North and South bound carriageways of the A470 are closed at Pontypridd and members of the public are being diverted away from the area where possible.
Police negotiators are currently in attendance.
Motorists are advised to avoid the area and to use alternative routes.