The Welsh assembly has been warned that its plans to reorganise the NHS are "in chaos".

The warning came after it emerged that three regional director posts remain unfilled despite being advertised in May - the directors are to oversee a new structure for the health service including next April's replacement of Wales's five health authorities with 22 local boards.

"It is chaos because the three regional appointments are pivotal to the whole organisation," said Kenneth Cross, a director of Dyfed Powys Health Authority.

"The assembly is in panic mode, probably trying to conscript three unwilling civil servants to take on these posts. If they are not of the right calibre, it would be a disaster."

He also warned that of the 22 local chief executives it was possible that only 10 would appointed because of a lack of applications.

Welsh health minister Jane Hutt launched the plans in November 2001.

The latest problems sparked an angry response from Plaid Cymru and the Welsh Conservatives.

Welsh nationalists said Hutt should take her plans "back to the drawing board".

Plaid AM and policy director, Cynog Dafis, said his party had warned that the plans were "over bureaucratic, ill conceived and would do nothing to save money or improve patient care" when they were first introduced.

"The reforms are irrelevant to any patient sitting in any waiting room in Wales," he said.

"They will not alter the fact that we have lost 6000 beds over the past 10 years and that Labour has a disastrous record on healthcare. That is why we need a simpler structure."

But Kirsty Williams, Liberal Democrat chair of the health and social services committee in the Welsh assembly, said the restructure would go ahead despite being "difficult, uncomfortable and unsettling" for staff.

"People will understand that local organisations will be commissioning services on their behalf and they will be assisted by a regional tier," she said.

Nick Bourne, leader of the Conservatives in the Welsh assembly, criticised Hutt for leaving it to her "coalition chum" Williams to defend the policy.

"Instead of Jane Hutt, as minister for health, addressing this issue, we have been subjected to the views of her coalition chum, Kirsty Williams, whose working background is in marketing and public relations. The NHS is far too important to be left to political spin," said Bourne.

"Jane Hutt's refusal to stand-up and justify her own action this week is nothing short of scandalous."