The meeting is being held ahead of a two-day summit of the European Union where a decision will be made on the start of membership talks with Croatia and Turkey. The meeting of the European Council starts on Thursday evening.
Sanader told reporters upon arrival that there was still a possibility that the European Council would decide to open membership talks with Croatia in March next year.
"There are two possibilities now. One is that negotiations will open in March, and the other is in April," the Croatian prime minister said.
Sanader said that he would insist in his talks with EPP leaders that negotiations on Croatia's full membership of the European Union should start next March.
Commenting on reports that the start of the entry talks would be made conditional on cooperation with the UN war crimes tribunal in The Hague, Sanader said: "Croatia has the obligation to cooperate with the Hague tribunal anyway, and the EU has a suspension clause by which it can suspend negotiations at any time if a country does not meet all conditions."
"My position is that no additional conditions are necessary. If it is accepted, fine, if not, fine again, because what matters is that we get a date for the start of the talks," he added.
Sanader said that Italian Prime Minister Silvio Berlusconi had clearly told him in Milan last week that Italy would support Croatia unconditionally. "Problems have obviously arisen in Italian diplomatic channels, and I expect to get a confirmation for such a position when I meet Berlusconi today."
Asked to comment on reports that Italy sided with countries insisting on Croatia's full cooperation with the Hague tribunal as a condition for the start of the membership talks, Sanader said: "It's a misunderstanding, noise in the communication channel."
The EPP, the largest faction in the European Parliament, gathers Christian Democrat and Popular parties from around Europe. Today's meeting will focus on forthcoming decisions of the European Council on opening accession talks with Croatia and Turkey and on the situation in Ukraine.