The conclusion was confirmed by Drago Kos, a former GRECO president and an expert in combating corruption, in an interview with Wednesday's issue of Mostar's Dnevni List daily.
He said the Council of Europe insisted on a transparent financing of political parties in all member countries, including Bosnia, in which virtually nothing has been done in that regard.
"Your political parties won't accept that for one simple reason - they want to hide the origin of the money coming into their accounts," Kos was quoted as saying.
He said the European Union would not tolerate that and that it would demand that Bosnian authorities resolutely cracked down on corruption.
"Just like tackling corruption on the highest level was required of Croatia, just like the EU asked Serbia to examine the privatisation process, BiH could be required to do all that as well as examine the financing of its political parties."
Analysing how Bosnian political parties are financed, GRECO concluded there is no uniform legislation regulating that, so parties can finance their campaigns from various sources and submit only partial reports limited to certain periods of time.
Carrying GRECO's predictions, Sarajevo's Oslobodjenje daily said political parties were expected to ensure timely and integral access to information on financing sources, including lists of donations and donors' names.
Parties are also expected to effect all their financing via bank accounts, which has not been the case so far, making it impossible to precisely follow the money trail.
According to the Central Election Commission, in 2010, when the country held the last election, the Party of Democratic Action (SDA) received the highest amount from public sources, more than EUR 2.15 million. It was followed by the Social Democratic Party (SDP) with EUR 1.6 million, the Party for BiH (SBiH) with EUR 1.25 million, the Alliance of Independent Social Democrats (SNSD) with EUR 1.2 million, and the HDZ BiH with EUR 800,000.
The SBiH spent the most on its campaign, EUR 800,000, but won the lowest number of votes. The relative winner, the SDP, spent a little under EUR 700,000, the SNSD spent EUR 600,000, the SDA spent EUR 500,000, and the HDZ BiH spent EUR 300,000.
In order to make the financial transactions of political parties more transparent, GRECO gave the Bosnian authorities until November 30 to carry out its recommendations.
Kos estimated that Bosnian politicians would stall as much as possible with implementing the recommendations, saying this raised many questions and concern.