The motion - supported by the Conservatives and Liberal Democrats - followed a debate to ratify the National Assembly's budget.

Worded simply, the motion read "The National Assembly has no confidence in the First Secretary".

Assembly Members will debate the no-confidence motion on Wednesday at 1430GMT before Mr Michael replies then a vote will be taken between 1515-1530GMT.

If the vote is carried, the Labour party will hold an emergency meeting to decide on what course of action to take next.

Plaid's Acting Leader Ieaun Wyn Jones said Mr Michael had "let Wales down badly".

Mr Michael is accused by opposition parties of failing to secure additional funding for Wales under the Objective One European regeneration scheme.

"Mr Michael should have made the case for Wales to get the money it deserves much stronger," said Mr Jones.

"The people of Wales realise this and this is why we are confident that the people of Wales are behind our actions."

Mr Michael said the vote was tied in to a "meaningless and arbitrary deadline".

"The money is there and we have been consistent and honest in our explanations."

Economic Development Secretary Rhodri Morgan acknowledged that Mr Michael may not be First Secretary in a week's time.

Mr Morgan - who lost out to Mr Michael in a party leadership contest - said he thought the First Secretary would survive.

"But to some extent it depends on procedure and the rules for those procedures have not yet been written," said Mr Morgan.

"The phrase 'unchartered waters' is hardly adequate to describe the uncertainty of what will happen over the next seven days."

Earlier, a former government minister urged the Assembly First Secretary Alun Michael to resign.

Cardiff Central MP Jon Owen Jones told the BBC that Mr Michael was "extremely unpopular", and that making him the party leader in Wales had been a "mistake".

Mr Jones said Mr Michael's resignation would be the only way for the Labour Party to recover its reputation in Wales.

"It's not an exaggeration to say the future of the Labour Party in Wales is at stake," he said.

"What we have to do is decide whether we want to continue to face further punishment or whether we should move on.

'Stand aside'

"To move on, it requires new leadership and I think that Alun should stand aside."

Plaid Cymru has insisted on the Treasury providing match-funding for a �1.2bn aid package and claims Mr Michael has failed to achieve that guarantee.

The European funds - earmarked to help regenerate deprived areas - can only be accessed if pound-for-pound matching cash is made available.

Meanwhile, Mr Michael insists he will not stand down even if he loses a vote of no-confidence.

"I am the leader of the Labour Party in Wales and its nominee for First Secretary and nothing has changed around that," said Mr Michael.

The Opposition parties warned they would push ahead with further no-confidence motions should he be renominated by his party.

Labour MPs Don Touhig and Llew Smith have attacked Plaid Cymru over the party's attempts to "bring down" the Labour administration.

They warned Plaid not to "entertain the idea" of an alliance with Labour if they "force through the vote of no confidence" against Mr Michael.

A statement from the two MPs said that Labour was the "sworn enemy of the nationalists in our valleys".

Welsh Liberal Democrat Leader Mike German said: "Liberal Democrats are committed to voting against Alun Michael if he fails to come up with the matched funding for Objective One money before next Tuesday."