Hywel Dda is reminding visitors and patients that access to Withybush Hospital is via Fishguard Road only as work on the multi-million pound renal unit continues.
Patients are urged to allow extra time for appointments because of the ongoing building work and new traffic flow system.
There is no longer access via Withybush retail park.
The health board apologises for the inconvenience this may cause to patients and visitors accessing the hospital and has created a new patient drop off point signposted immediately to the right of the front door to facilitate ease of access to the main entrance.
Patients and visitors are urged to follow the signs for parking and not to drop off outside the designated area.
Mandy Davies, acute services general manager, said: “We apologise for any inconvenience caused while the building work is ongoing. The renal development unit will make such a difference to patients in Pembrokeshire and the new traffic system will also make the flow of traffic around the hospital site more efficient.”