Fareham Borough Council approved the application to reconfigure the car park to undertake a series of works.
The plan seeks to reconfigure not only the car park but the bus lane and Centre Way access road to improve circulation.
There will be additional planting, cycle lanes and a raised car park deck providing 66 spaces.
However, residents are worried that there would be fewer parking spaces after the work, which could have a knock-on effect on nearby streets.
A planning statement made on behalf of the applicant includes a table that shows there will be no changes to the 603 parking spaces currently available.
Julie Kidby, from the Fareham independent group said the access to some parts of the car park is unclear.
'The table gives the impression that there will be no change to the total of 603 spaces currently available, however this figure is arrived at purely due to the 66 spaces proposed for the parking deck which is apparently to "serve future development and intensification of the shopping centre rather than to replace the lost public spaces".
'In our opinion, this makes the future use of the parking deck entirely unclear.'
John Gorrod, local resident also objects to the plans: ‘There is nothing in the plan to encourage or promote the use of public transport, all it does is change the location of the bus stop.
‘Fareham's planning committee got it right when they approved the original design of the centre and I don’t think it impertinent to suggest that this proposal is only presented to suit the profit requirements of New River.'
Sean Woodward, leader of the council said: ‘I had some significant concerns that they would be losing levels of car parking - they’re not.
‘It’s a fantastic shopping centre. Nobody would like to see anything done, least of all the owners of the centre and the tenants, to damage its viability.’