"As far as corruption is concerned we are a sick society, and we must fight this," Mesic said on the occasion of International Anti-Corruption Day at an event organised by the Croatian branch of Transparency International (TI).
He said that although several good laws aimed at combating corruption had been adopted, they were not complied with.
The president of TI's Croatian branch, Antun Petrovic, said Croatia lacked political will to implement the anti-corruption laws or seriously tackle corruption.
He said the current presidential campaign would be a good opportunity to demonstrate such political will because every candidate would be able to reveal figures about the financing of their campaigns.
A member of the TI Management Board, Josip Kregar, presented the results of a public opinion poll on the perception of corruption in various institutions. The poll was conducted in 64 countries and covered more than 50,000 people.
According to the poll, corruption in Croatia affects the business sector the most, followed by politics and personal and family life.
The most corrupt sector in Croatia, according to the poll, is the judiciary, followed by political parties, parliament, the tax administration, the economy, customs, police, and health.