Norfolk County Council has been challenged to prove it needs to increase its parking provisions as it prepares to move hundreds of staff members into its headquarters.

As part of plans to relocate more than 500 members of staff from Carrow House to County Hall, the county council is looking to ramp up the amount of staff parking it offers.

However, planners at Norwich City Council - who will ultimately have to give the plans their approval - have warned the council will need a strong argument to justify any expansion.

Ahead of formal planning application being submitted, the county council turned to City Hall for guidance on how to go about the proposal with a variety of options.

However, in a letter sent to the county council, Robert Webb, wrote: "Currently there is a lack of information on the justification for the increase in parking and this information should be provided as part of any full application for the proposals.

"It is recommended that the applicant fully explores improved accessibility for more sustainable modes of transport before an increase in car parking is proposed. This could include improved facilities and connections for bus and cycle users, with a focus on improving links to and from the city centre."

The three options proposed for expanding the car park were increasing the size of the existing annex car park, making alterations to one of the existing car parks and a raised deck on the main car park.

A spokesman for Norfolk County Council said: "One of our long-term aspirations is to have an efficient and modern estate, building on the move and subsequent closure of Vantage House and Thorpe Road in Norwich.

"Our next step is to move approximately 540 people from Carrow House to County Hall within the next nine months.

"To accommodate around 360 staff members that do not have parking at County Hall, we are looking to increase the amount of spaces on site.

"We are also exploring other options including encouraging staff to use sustainable travel as well as walking and cycling.

"A formal planning application is likely to be submitted before Christmas and will take into account all the feedback from Norwich City Council."