The conference "Peace and Reconciliation - A Step Forward" is being held under the auspices of Banja Luka Bishop Franjo Komarica and scientists from Harvard University to promote peace and dialogue in the region. It brought together officials and representatives of non-governmental organisations from countries in the wider region.
Leko said he had not come to offer recipes but help in the joint search for solutions.
"This is one of the most important moments in the region's history. In less than a month, Croatia will be a member of the EU. We are confident that the beneficial effect of that will be felt in the entire region, including Bosnia," he said.
The Euro-Atlantic integration of all of its neighbours is a priority for Croatia and this especially refers to Bosnia, which must be a stable and functioning state with equal rights for all of its peoples, Leko added.
He said Croatia had proved many times its advocacy of the refugees' right to return, ensuring it for 133,000 of its own citizens and more than 40,000 Bosnian citizens. He recalled the reconstruction of 150,000 housing units and the restitution of 19,000, as well as the fact that more than 2,000 homes in Bosnia had been rebuilt with funds from the Croatian budget.
Warning about the outstanding issues, he highlighted the fact that many Bosnian refugees had not managed to return yet.
"We believe everyone knows that Republika Srpska has remained without 95 per cent of its Catholic population," Leko said, adding that only 12,000 of the 200,000 expelled Croats had returned to the Bosnian Serb entity and that Bosnia's Croat population numbered only a little over 450,000, nearly twice less than before the 1992-95 war.
Facing those facts is extremely important to strengthen peace, Leko said, calling on everyone who could do so to further push for sustainable return as the only way for Bosnia to move on. He added that Croatia would continue to support them in that.
Leko went on to say that Croatia supported the continuation of the international community's engagement in Bosnia. "There is no better path to a better future than reconciliation."
Bosnian lower house speaker Bozo Ljubic said everyone in Bosnia was a victim in a way and that the only way to build a better society was by openly talking about frustrations. "The only way to reconciliation and cooperation is justice."
Ljubic said there was no stable Balkans or Europe without a stable Bosnia and that there would be no such stability as long as Bosnia functioned on the foundations of the Dayton peace agreement and as long as there was no consensus on how to handle important problems.
He warned that Croats, disgruntled with the situation in Bosnia, continued to emigrate and that this could have dangerous repercussions for the country. "One gets the impression that the Croats' intended role is that of collateral damage," Ljubic said, calling for open dialogue on outstanding issues.
Republika Srpska Parliament Speaker Igor Radojicic said Bosnia needed an "irreversible state of stability" and that it often looked as though "Sarajevo and Banja Luka differ not only by political goals but they also don't hear and don't understand" each other.
"Everything can fall apart in a moment because progress isn't a one-way process and it isn't guaranteed. A little distraction is enough to jeopardise those achievements," he said, alluding to the constant political conflicts in the country.
Montenegrin Parliament Speaker Ranko Krivokapic said the European prospect remained his country's commitment and expressed willingness to fully contribute to reconciliation as a prerequisite for strengthening stability in the region.
A member of the European Parliament and its rapporteur on Bosnia, Doris Pack, also warned that the situation in the country was still not stable and that everyone should ask themselves why. She said one of the important outstanding issues was the existence of schools in which students were still taught different curricula, depending on ethnicity.
Education has an outstanding role in peace-building, she said, calling for following the example of schools founded by the Catholic Church in Bosnia in keeping with European values.
Pack said she had not come to criticise anyone but because she loved Bosnia and that this was the motive for her advocacy in the European Parliament of a stricter resolution on Bosnia, in which she also recommended suspending the country's membership of the Council of Europe.
Serbian Parliament Speaker Nebojsa Stefanovic said Serbia was ready to leave the past behind and build a common future in the region based on European tenets.