Opposition parties have strongly criticised a party organised by the Welsh Assembly Government to mark a fall in NHS waiting times.
The party was held at the Senedd on Wednesday
The reception for 70 NHS professionals was held at the Senedd in Cardiff.
The assembly government said the event recognised achievements in reducing waiting times but the Liberal Democrats said it was insensitive.
Conservatives said it was a slap in the face for those on waiting lists while Plaid Cymru said the NHS was in crisis.
First Minister Rhodri Morgan and Health Minister Brian Gibbons hosted the "celebratory event" on Wednesday evening to thank health professionals for improvements in NHS waiting times.
The most recent waiting list figures, released on 26 April, showed that at the end of March there were no patients waiting more than 12 months for inpatient treatment or day case surgery.
There was also a major reduction in the number of patients waiting 12 months for a first outpatient appointment.
The assembly government said the event was an opportunity for health service managers to have informal discussions about how further to reduce waiting times.
It added that the cost is not being met from the NHS's own budget, but was being paid for out of the assembly government's hospitality budget.
All Welsh NHS trusts were invited to send up to six representatives to the party while local health boards have been asked to nominate two guests each.
The guests attended a buffet reception before taking a short tour of the new assembly building in Cardiff Bay.
Mr Morgan said: "I would like to pass on my sincere thanks to all staff who have worked so hard to improve waiting times in Wales, whilst at the same time maintaining the momentum in the other priority areas.
"Most people's experience of waiting times is shorter still than these maximum waits. Most people are waiting three months or less and eight out of 10 people are waiting six months or less."
But opposition parties said the event was inappropriate.
Liberal Democrat health spokesperson Jenny Randerson said the party was hugely insensitive on a day that nurses were lobbying the assembly over financial problems in the NHS.
Ms Randerson said many patients would feel there is no cause to celebrate and that any thanks should go to the clinical staff and nurses rather than NHS managers.
Welsh Conservative health spokesman Jonathan Morgan asked if the event was a "sick joke".
He added: "To hold a celebratory event for the so-called success on waiting times is at very best a badly thought through publicity stunt which only serves to highlight Labour's Achilles heel.
"This is a slap in the face for all those patients who are still waiting for treatment because of Labour's incompetence in running the NHS in Wales."
Plaid Cymru health spokesperson Helen Mary Jones said the event "beggars belief".
She added: Staff in the NHS are hard working and should be congratulated but they are working to policies set out by this government which are failing and targets set by this government which are not being hit.
"I wonder if the 40,533 people who...are waiting more than six months for an outpatients appointment would wish to add their congratulations to a government presiding over an NHS which is in crisis."
Commenting on the criticisms, an assembly government spokesperson said: "Criticisms that have been made of the event for NHS staff are totally inappropriate.
"The event is being held to recognise the achievements that have been made in reducing long waiting times over the past year. It is not an event for NHS 'managers'.
"The people attending tonight range from clerical staff to medical directors and will give the first minister and health minister an opportunity to thank them and to discuss the next steps in reducing waiting times."