An investigation is underway after a bus hit several parked cars at Llandough Hospital.
It happened in the multi-storey car park at around 2.35pm on Thursday afternoon.
No one was seriously injured but two cars were forced over a ledge after the bus reportedly careered off the road and crashed through a barrier and a fence, ending up hanging over the edge.
Cardiff and Vale health board (CAVUHB) is asking visitors to the hospital on Friday to allow extra time for their journey.
A CAVUHB spokesperson said on Thursday evening: "The bus has been safely removed and work is ongoing to remove the cars involved."
They added: "Access to the car park is currently restricted to new vehicles but people are able to enter to retrieve vehicles already parked inside."
"We currently have professionals on site to assess the car park and confirm it is safe to reopen."
South Wales Fire and Rescue Service says it sent out crews from Penarth and Cardiff Central after receiving a call at approximately 2.37pm.
They assisted with setting up a cordon and moving vehicles to make the scene safe.
A spokesperson for South Wales Police confirmed there were no serious injuries in the incident, adding: "The circumstances surrounding the collision are being looked into."
Cardiff Bus said its services were unable to access the hospital grounds with buses picking up and dropping off passengers on the main road.