Croatia on Friday resumed talks on joining the European Union, stalled for more than a year because of a border dispute with EU member Slovenia, Reuters reported. The resumption, made possible after Slovenia agreed to lift its veto, has revived Croatia's hopes of becoming the bloc's 28th member and coincides with a vote in Ireland on the Lisbon treaty, which will be essential to further EU enlargement. EU Enlargement Commissioner Olli Rehn said it was a breakthrough. "I would say that this is not only a win-win situation for Slovenia and Croatia, it's a win-win-win, because it is also a victory for the European Union if we can unblock the negotiations with Croatia and see that the border dispute is settled," he told reporters. Zagreb was due to open negotiations on six new "chapters" and close five at an accession conference in Brussels, presided over by the Swedish EU presidency. "This means we have entered the final phase of our negotiations to become an EU member," Croatian Prime Minister, Jadranka Kosor, told reporters while visiting the northern Adriatic island of Krk. The Slovenian and Croatian foreign ministers, Samuel Zbogar and Gordan Jandrokovic, were due to discuss setting up an arbitration tribunal to oversee final settlement of the border dispute. "I expect good talks and important steps forward to be made," Jandrokovic told reporters. Asked whether the two sides could initial an arbitration deal, he replied: "We are continuing talks in good faith and I am sure there will be important steps forward." The resumption of the membership talks has renewed Croatia's optimism that it can finish EU negotiations by next July. It still needs to step up its fight against corruption and make its courts and public administration more efficient, which would go a long way towards attracting foreign investment. It also must show it is cooperating fully with the U.N. war crimes tribunal for former Yugoslavia. The tribunal's chief prosecutor, Serge Brammertz, who has requested military documents from Croatia, visited Zagreb this week and a senior Croatian government official said he left with few signs of progress on this issue. Rehn said there was still important work for Croatia to do to complete its EU talks, which would be addressed in a progress report due to be issued on Oct. 14. "But let's have some joy today and celebrate the reopening of the negotiations and we come back more seriously back to this important issues in two weeks," he said. Asked if Croatia could still join the EU if there was a "no" vote in Ireland in a second referendum on the Lisbon treaty, Rehn replied: "It's very important that we can make the European Union more effective and democratic and reinforce our capacity to act in common foreign and security policy. "We would have needed the Lisbon Treaty yesterday, not only for tomorrow. I trust that Croatia will join the European Union once it meets the conditions." A rejection by Irish voters would spell the end of the treaty and Croatia, next in line for EU membership, might be the only country to enter the bloc for several years. Political analysts say accession talks with Turkey could be frozen, discouraging further reforms there.