First Minister Rhodri Morgan was last night facing weeks of negotiations with opposition parties after they branded his budget plans 'totally unacceptable'.
Without a majority in Cardiff Bay, Mr Morgan will now have to compromise with the other parties to get the £14.5bn spending plans approved.
A repeat of last year's tortured process now seems likely, with AMs having until December before a deal must be reached.
Finance Minister Sue Essex yesterday unveiled the draft budget, which promised modest rises for dentistry, roads and local health boards. She said she would be 'surprised' if the measures were opposed, but just two hours after her announcement the other parties put forward their own 12-point spending shopping lists.
The leaders of Plaid Cymru, the Tories and the Liberal Democrats said they would table an amendment to the budget when the Assembly first votes on it next Tuesday.
Plaid leader Ieuan Wyn Jones said, 'The draft budget published by the Finance Minister today is unacceptable.
'School budgets are being stretched to the limit, the ambulance service is severely underfunded, and the Government is showing a total disregard for farming and rural communities. We will not agree to a budget that doesn't provide a fair deal for the people of Wales.'
Sitting next to Mr Jones, Conservative group leader Nick Bourne rejected Ms Essex's claim that she had stretched the Government's coffers to the limit in drafting the £14.5bn budget.
'There is room for manoeuvre and we certainly do expect movement on these reasonable demands,' he told reporters.
'I think the budget has been disappointing but last year we had careful and constructive opposition in drawing up the final budget and I anticipate we will do the same this year.'
Earlier Ms Essex said she only had an additional £74m to spend on public services next year.
Within that the Government has set aside an extra £5m for dentistry, £15m for roads and £9m for local health boards. An all-Wales coastal path would get £1m, if approved by AMs.
She said it was important to wind up the budget and get it through the Assembly quickly so front-line staff knew where they stood.
'I have certainly done my best to listen to the opposition and take into account the things they are particularly concerned about,' she said.
The opposition has the support of independent Trish Law and Forward Wales AM John Marek who have put forward their own pet projects.
The increasing willingness of opposition parties to work together is a feature of Cardiff Bay politics, and a successful attempt to change the budget will prompt more speculation that a formal coalition could follow next May's elections.
Lib-Dem Assembly leader Mike German said, 'This is a package put together by the opposition leaders with Trish and John Marek as well, and it represents a view across the Assembly. And given it's a majority view you would have expected the First Minister not to have brought a lot of trouble on his head by the process he has now engaged in.'
Although it will not reveal the total cost of its demands, the opposition is asking for a range of measures including a bigger budget for the ambulance service; the funding gap between England and Wales' universities to be closed; a restoration of the Tir Mynydd farming grant scheme to last year's levels and more money for disabled children's play areas.
The Government said Ms Essex had already met opposition leaders on many points and their proposed amendment merely repeated issues put to her last week.