He is visiting Sarajevo as part of a consultative task force reviewing the situation in Bosnia.
In a statement to Dnevni Avaz daily of Friday, Priebe said the Commission attached great importance to the precise implementation of free trade agreements.
He declined to say who was right in Bosnia's free trade disputes with neighbours, but said the authorities would be asked about the treatment of Slovene goods on the Bosnian market given that Slovenia is a member of the European Union.
Commenting on Bosnia's ambitions to draw closer to the Union, Priebe said Bosnia could not count on stabilisation and association talks starting soon because it had not met the terms set by the European Commission.
He said Bosnia had made significant progress in reforms Brussels insisted on, but added the two main issues -- cooperation with the Hague war crimes tribunal and police reorganisation -- remained outstanding.
Priebe said that at the moment it could not be said that Bosnia had achieved progress in 16 areas Brussels insisted on.
Bosnian officials had said previously they expected the stabilisation and association talks to start in May.
Priebe said the consultative task force would meet again in May, when it was likely to give a clearer as well final answer to how far Bosnia had made it in terms of reform.
Explaining what full cooperation with the war crimes tribunal in The Hague meant, Priebe said some recent surrenders of indictees had been a good signal but that the number of those who surrendered could not be deemed satisfactory.
Priebe said the restructuring of the police force on the state level was another term for Bosnia's further EU integration.