Doctors belonging to the British Medical Association in Wales have backed consultants in their contract row with the Welsh Assembly Government.
NHS consultants have been locked in a dispute over pay
They have agreed a vote of no confidence in the assembly government's handling of the long-running dispute over overtime pay for NHS consultants.
The consultants say they have not been paid for overtime since they voted to back a new contract in 2003.
The assembly government said it was ensuring consultants are paid properly.
Under the new contract, signed in December 2003, the consultants agreed to work a minimum of 37.5 hours a week for the NHS and be paid overtime for any hours worked beyond that.
But they had criticised the assembly government for having failed to implement the contract more than a year later.
Speaking on Wednesday, Welsh Health Minister Brian Gibbons said the money was in place and he hoped an agreement could be reached.
But on Thursday, the BMA's Welsh Council announced it had unanimously backed the Welsh consultants' motion of no confidence in the assembly government's handling of the contract row.
The organisation said that Dr Gibbons had showed honesty and sympathy but that he had been "landed " with the situation.
Jonathan Osborne, the Chair of the Consultants Committee, said there had been incompetence from the assembly government and they could not continue to support an administration presiding over such a "calamity".
The BMA called on Dr Gibbons to rebuild consultants' trust in how the assembly government manages the NHS.
It said it had no plans to take industrial action but said it would back members pursuing payments through the courts and would have "no hesitation" in supporting members via an employment tribunal.
Following a two-hour debate, the Welsh council for the BMA voted unanimously on for the motion: "The BMA Welsh council has no confidence in the ability of the Welsh Assembly Government to fully implement consultants' contracts."
The consultants said they hoped the public would understand their actions and that they would support them.
They stressed that unless the consultants' contract was implemented, then the consequences would be "disastrous" for the Welsh NHS.
According to an assembly government spokesperson, with £37m being spent on the contract, £18m of which is earmarked for overtime payments, it was vital that taxpayers knew they would be getting value for money.
The statement added: "It is regrettable that the consultants feel this way.
"The Welsh Assembly Government has been fully committed to ensuring that consultants benefit from the massive investment we've made in the contract."