No new members will be admitted to the EU unless they are fully prepared, the European commissioner for enlargement has said.

Countries would not be admitted which needed follow-up monitoring, said Stefan Fule, in a reference to Romania and Bulgaria, which joined the EU in 2007 but needed continued scrutiny due to problems with corruption and organised crime. He said “lessons have been learned” on ensuring members were ready to join before being admitted.

“It is important to try and strengthen the credibility of the process,” said the commissioner, after a meeting in Dublin of Europe ministers of EU member states and countries hoping to join the union.

Enlargement of the EU made good economic sense since many candidate countries had growing economies, said Minister of State for Europe Lucinda Creighton, who chaired the meeting as part of Ireland’s EU presidency. It was also vital for the European economy that there was stability in the western Balkans. “It is very much in our economic interest that we encourage these countries along the European path,” she said.

Ireland wanted to see progress on countries trying to join the EU, especially Serbia and Montenegro, she said. “We see a big opportunity to inject some momentum into the process,” she added.

Ministers also discussed the possibility of political groups in the European Parliament nominating candidates for president of the European Commission next year.

The move was proposed as a way of promoting democratic legitimacy. Other ideas discussed included giving national parliaments a greater say on EU affairs and an oversight role on the commission’s monitoring of national budgets.

Paul Murphy, Socialist MEP, said the Minister’s talk of democratic accountability was an “insult” given new rules under the European Semester were due to begin which would give the commission greater oversight of national budgets. The rules could impose “semi-colonial status” on some countries, he said in a statement.