Estimating that Croatia could become the Union's 28th member, Rehn said the treaty on Croatia's accession could be used to reorganise the EU's institutions in line with proposals put forth in the Constitution.
"Depending on how the constitutional reform will proceed... it might be worthwhile considering that the accession treaty of Croatia would provide possibilities to make some amendments to the institutional rules of the European Union, including the
size of the Commission," Rehn said in answer to questions after a speech at Berlin's European Policy Institute (EIP), according to Reuters.
"It would save some of the most commonsensical, necessary elements of the constitutional treaty, to make decision-making of the European Union more effective and efficient," Reuters quoted Rehn as saying.
In his speech Rehn reiterated the Union was ready to open negotiations with Croatia as soon as it was evaluated that it was fully cooperating with the Hague war crimes tribunal.