The treaty, which foresees a two-year president while also maintaining a rotating presidency for running business, is due to enter force as soon as EU states ratify it, which would be by the beginning of 2009 at the earliest.
“The new treaty will be disruptive for the whole environment,” Swedish state secretary for European affairs Håkan Jonsson told a conference in Strasbourg.
The rotating presidencies “will be a nightmare for us, because it is such a changing time”, Jonsson said.
Once EU members ratify the treaty, the new president will have to be bolted on to the bloc’s existing institutions.
“We need to ensure a balance between the permanent president and the six-month presidency,” said Czech vice prime minister in charge of European affairs Alexandr Vondra.
The new two-year president is one of the main innovations of the Lisbon treaty, which the bloc’s leaders signed last month in the Portuguese capital and which is supposed to streamline the EU’s main institutions.
The treaty is supposed to replace the EU’s constitution, which was abandoned after French and Dutch voters rejected it in referendums in mid 2005.