A survey canvassing patient's opinions of the current pay-all system will be completed by June. The current system requires the SSO to make large advance payments to hospitals, regardless of the number of beneficiaries who actually make claims.

In the event of the reintroduction of the reimbursement plan, dental costs would be increased from the rate of Bt200 per visit twice a year to Bt600, Bt800 or Bt1,000, while hospital delivery costs would be fixed at Bt10,000, he said.

Phairoj said that despite widespread criticism of the pay-all system he had also received direct calls of support from a number of beneficiaries of the scheme.

Referring to dentists' claims that the free dental care scheme had burdened them with extra work, Phairoj said: "The SSO is the client in this context. If the dentists know that they don't have enough manpower, it's their job to produce more personnel to cope with demand."

Dentist Suphaphol Iammetha-wee, a vice chairman of the Private Dentists' Association of Thailand, said the association had warned caretaker Labour Minister Somsak Thepsuthin that the free dental care initiative was unlikely to be able to fully cater to the public's requirements. He proposed that dental services should only be free of charge for those on low incomes, while patients with higher incomes should contribute towards the costs.

Wilaiwan sae-Tia, head of the Thai Labour Unity Commission, voiced her support for the return of the original system, saying the current pay-all system mainly benefited private hospitals. She said the commission would hold a meeting with other labour groups on June 3, to discuss further solutions.