Plaid Cymru's leader is demanding a better offer from First Minister Rhodri Morgan after effectively rejecting his offers of co-operation.
Ieuan Wyn Jones said he accepted parties would have to work together
In a letter to Ieuan Wyn Jones, Mr Morgan outlined areas where the minority Labour administration and the Plaid Cymru group could work together.
But Mr Jones said the offers would not lead to the "stable government" the people of Wales needed and deserved.
Mr Morgan said he was aiming to hold further talks with opposition parties.
Following May's assembly election, Labour was five short of a majority and is now running a minority government, which means its policies will need support from other parties.
Last week, Mr Morgan wrote to both Plaid Cymru and the Liberal Democrats suggesting ways of co-operating.
Among the offers he made was an inquiry into the Barnett formula, which determines the way the Welsh assembly is funded.
He also offered a temporary halt to changes to Welsh hospital services, and a group to examine the conditions for a referendum on Scottish-style powers for the assembly.
Rhodri Morgan said he was looking forward to discussing the issues
Writing in response, the Plaid leader said he fully accepted the parties would have to work together during the period of the Labour minority administration.
However, he said he did not feel the arrangements would "in the long term give the people of Wales the stable government they need and deserve".
Mr Jones went on to reject an inquiry into the Barnett formula by the assembly's finance committee on the basis that it was not "an appropriate forum".
He cautiously welcomed the temporary halt on NHS reconfiguration, but said any future consultation must be "meaningful" and "take the views of local communities fully into account".
But he said the proposal for a group to discuss the conditions for a referendum on further powers for the assembly was "unacceptable", and called it a "delaying tactic".
The proposal for regular meetings would be useful, but would only be constructive if the subjects discussed "have a real impact on the government's programme", he said.
Responding to Mr Jones's letter, Mr Morgan said that he "is hoping to meet the leader of the opposition and is looking forward to discussing these issues in good faith."
Plaid Cymru's national council will meet on 7 July in Aberystwyth to discuss whether or not they endorse the proposal for a coalition between themselves, the Liberal Democrats and the Conservatives.