Gyurcsany said it was inconceivable the EU could open the door to Turkey but leave one of Europe's biggest countries out in the cold.
Polish President Aleksander Kwasniewski recently said Brussels should start membership talks with the new, reformist government in Ukraine as early as 2006.
New EU members from the former communist world have emerged as strong supporters of the accession hopes of Ukraine and other countries that have so far failed to secure clear signals about the prospect of membership.
Gyurcsany also said Thursday Croatia was doing all it can to comply with EU demands it hand over General Ante Gotovina, who is wanted on suspicion of war crimes by the International Court in the Hague.
Croatia's EU membership bid was put on hold last month over concerns authorities in Zagreb were not doing enough to locate the fugitive.