Kovacevic, who today froze his membership in the HKDU, told a news conference that he expected excellent results at the polls and that he would stand in the second election round.
He added that he would not have run in the presidential race, had the ruling Croatian Democratic Union (HDZ) nominated Deputy Prime Minister Andrija Hebrang for the election.
After the HDZ nominated Deputy Prime Minister Jadranka Kosor, Kovacevic decided to take part in the presidential race because he believes that "it is a must to replace" the current president, Stjepan Mesic.
He said he approved some moves by the current head of state, but he could not accept what he labelled Mesic's "servile mentality".
Kovacevic added that the time was over when Croatia had "to curry favour with every Eurocrat visiting Zagreb".
He said that funds for his presidential campaign would come to "a modest 10,000 euros".
Present at the news conference was a US businessman of Croat descent, Boris Miksic, who has also announced his presidential candidacy. He said he had come to this press conference out of respect for Kovacevic "who, like me, has never been even a half an hour a member of the Communist Party".