In a statement, Duff said: "It is time to stop avoiding some tough questions about the why, when and how of EU treaty change. If the European Union is to be saved it needs a strong economic government. This means delicate treaty change prepared by a good Convention.
"Here is an ambitious but feasible agenda for the Convention. The intention would be to run the Convention from March to September, and to work intensively to produce a firm consensus on the conferral of fiscal competences on theUnionand on the legal and political nature of economic governance.
"A high priority will be to reach agreement on how the EU's new fiscal and economic policies will strike a balance between stability and growth on the one hand, and solidarity and discipline, on the other.
Duff, who is spokesman on constitutional affairs for the Alliance of Liberals and Democrats for Europe (ALDE) and President of the Union of European Federalists (UEF), added:
"Executive authority will be shared between Commission and Council, but with the Commission in the driving seat. I propose a single legal framework based on the Treaty of Lisbon, and will strongly resist the temptation of a freelance intergovernmental treaty outside the EU-framework.
"The Convention must also tackle the problem of how to ensure ratification of the new Treaty."
See the Convention agenda