Speaking at a news conference on Tuesday, Djapic said that the visit was not prepared well and that "clear relations cannot be achieved only by mutual glorifying and support, without clearing up what happened in the early 1990s".
The HSP leader also criticised Sunday's interview with Serbian Television director Aleksandar Tijanic on Croatian Television (HTV).
"Tijanic used the most powerful medium in Croatia to relativise the Serb aggression," Djapic said, adding that "there is a little too much nostalgia on HTV".
He announced that HSP members would meet today other opposition clubs of deputies to try and reach agreement on a joint candidate for a member of the Commission on Conflict of Interest.
"If the opposition fails to reach agreement on a joint candidate, let the Sabor vote on all candidates individually," Djapic said adding that "further obstruction of the Commission's work is intolerable".
He condemned a statement by the head of the Office for the Prevention of Corruption and Organised Crime, Zeljko Zganjer, who commented on the Supreme Court's ruling in the cases of former foreign minister Mate Granic and public prosecutor Krunoslav Canjuga.
"Nowhere in the democratic world is a judicial official allowed to comment on Supreme Court rulings," Djapic said urging the government and the justice minister to comment on the case.
Party vice-president Miroslav Rozic described as intolerable the signing of a memorandum of agreement between Croatia and the US army on the use of Croatia's air space, training ranges, air and naval ports and training facilities by the US army without the knowledge of Croatia's Armed Forces Supreme Commander, President Stjepan Mesic.
He said that the government had also promised to promptly ratify the memorandum, which he said required a two-thirds majority vote in the parliament.
"The government obviously has a problem with the deployment of Croatian soldiers outside Croatia, but not with the entry of a foreign army into Croatian territory," Rozic said.