Controversial changes to parking charges are coming into force a Norfolk hospital.

Visitors to the Norfolk and Norwich University Hospital (NNUH) using an adjacent private car park will now have to pay for their car parking up front, with the ability to top up their payment if their appointment takes longer than expected.

The 310-space car park, which opened in 2013, is owned and operated by Bullen Developments, a subsidiary of construction firm R G Carter.

While the cost of parking charges will not change, people have expressed concern, confusion and frustration with the new payment system due to the sometimes unpredictable nature of the length of a hospital visit.

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An NNUH spokesman said: "The car park adjacent to the NHS hospital is a private business operated independently by R G Carter/ Bullen Developments and is not connected with the running of the hospital in any way. It is of course conveniently sited for our patients and visitors.

"The trust was not consulted in advance of the changes to the operation of the car park which we understand was implemented on Wednesday and was a surprise to us. We sympathise and understand the frustration of our patients and visitors.

"We are in discussions with R G Carter/ Bullen Developments about the way this has been handled and what mitigation measures they are putting in place to improve the way their car park operates and avoid the inconvenience which patients and visitors have experienced."

A spokesman for Bullen Developments said: "Following feedback from our customers we implemented a new on-site system to provide more payment options and introduced camera recognition, which allows faster and smoother entry to the car park.

"Under the new system the car park charges have remained the same and people have the flexibility to top-up their parking should their planned visit take longer than expected.

"We apologise for any inconvenience caused during the changeover work, and will be monitoring the system to ensure that it works efficiently and effectively for all users."