A review of car parking charges at NHS hospitals has been ordered by the Scottish Government.
The issue has been raised by hospital visitors and staff
Health Secretary Nicola Sturgeon said visitors and staff should be protected from unnecessary or excessive charges.
The move comes days after the public sector union Unison said it was to ballot NHS Greater Glasgow and Clyde staff on strike action.
The health board welcomed the review. Hospital authorities said the charges were important in tackling congestion.
In some hospitals visitors can be charged up to £7 a day.
The review will examine the impact of charges on staff, particularly lower paid workers.
It will also consider the appropriateness of blanket policies.
Ms Sturgeon said: "Car parking charges are a legitimate response by NHS boards to the difficult problems of congestion and ensuring adequate space for patients and visitors.
Car parking charges will be introduced at the RAH later this year
"However, people working or visiting hospitals across Scotland should be protected from unnecessary or excessive charges.
"The cost of hospital car parking, especially for lower paid members of staff who do not qualify for a parking permit, can be a large expense."
The minister added: "I understand the concern that has been expressed to me by many people who work in the NHS."
NHS Greater Glasgow and Clyde said it would play a full part in supporting the review.
A spokesman said: "It is clear there are challenges faced all over Scotland in ensuring that patients, visitors and staff who need a car for vital duties can access hospital car parks when they need to.
"Our existing policy will remain in force during the review."
The health board said it would continue with plans to introduce car parking charges at the Royal Alexandra Hospital (RAH), Southern General Hospital and Stobhill Hospital later this year.
The review group is expected to report back to Ms Sturgeon in November.
It will be the second time that hospital parking charges have come under top-level scrutiny.
In February, the then First Minister Jack McConnell told NHS bosses to reconsider charging arrangements after he was taken to task by angry nurses at a public meeting in Glasgow.
New arrangements have since been introduced at Glasgow hospitals, cutting the maximum daily parking charge from £12 to £7.
The number of patients and visitors qualifying for free parking was widened and a sliding scale was created for staff permits.