The Welsh NHS must stop paying for some its staff to receive treatment privately, says the health minister.
Edwina Hart said she would "not normally expect" local health boards and trusts to fast-track their staff through the health system.
But figures released to Plaid Cymru show that seven NHS staff members in south Wales received private treatment in the last three years.
The health boards involved said it was to ensure they had quick treatment.
The Aneurin Bevan Health Board, which covers the south east Wales area, revealed that it paid out £780 in 2008 involving two NHS staff and £1,600 for four cases in 2009 to be treated privately.
Cardiff and Vale University Health Board said there had been one "exceptional" case during the past three years where private sector treatment was used.
The areas of treatment were not identified.
Other health boards said they had not used private healthcare for their staff over the last few years.
But Ms Hart said her officials had "advised the new local health boards not to adopt this policy in future".
In a letter replying to Plaid AM Leanne Wood, who had raised the issue with her, she said: "I would not normally expect a local health board or trust to pay for a member of staff to receive private treatment.
"However, my officials have made inquiries to find out why they, or their predecessor bodies, paid for employees to receive private healthcare in the past.
"I am not able to provide any specific details because of patient confidentiality.
"But I understand that in these exceptional cases the health bodies in question took the view that, rather than allow the staff concerned to spend a lengthy period on sick leave with the attendant costs of finding locums on a temporary basis, it was considered preferable from an NHS cost and patient treatment perspective for them to receive private treatment."
Plaid Cymru South Wales Central AM Chris Franks, who originally wrote to all Welsh NHS boards to ask whether any staff had received private treatment, said: "I find it amazing that NHS bodies should be using the private sector for treatment of their staff, albeit a small number.
"But the number is not the point. What sort of message is this sending out to the public - you continue queuing, but we will use private healthcare?"