Car parking charges are to be introduced at Withybush Hosptal, Haverfordwest, in the spring, despite senior health managers acknowledging that the levy will be very unpopular with staff and visitors.
Pembrokeshire and Derwen NHS Trust, who run the hospital, say the charges are necesary.
According to the Trust, car parking fees will provide a cash boost of £250,000 a year to the Trust's income.
The funds will be used to provide additional car parking spaces and improvements to the car park facilities in general.
It also means that healthcare funds will not be utilised for such improvements. Surplus monies generated by the scheme would be spent on patient care.
During their January meeting, members of the Pembrokeshire Community Health Council voiced concerns at the impact of the charges on staff and patients, especially the elderly and disabled.
The Trust's chief executive, Frank O'Sullivan, said there would be exemptions for those who were unfairly disadvantaged by the charges.
One CHC member dubbed the levy a stealth tax on health, but Mr. O'Sullivan defended the controversial fees. He said the Trust was reluctant to impose car parking charges, but they were a 'necessary evil'. He also explained that almost all hospitals had now introduced charging arrangements.