Sweden takes over the EU chairmanship from the Czech Republic on 1 July.
Reinfeldt made the statement in an address to a group of reporters attending a seminar in Brussels organised by the Centre for European Political Studies (CEPS).
The Swedish official said that it was necessary to solve the current border dispute between Slovenia, an EU member, and Croatia, so that Croatia's EU membership talks could resume.
The dispute should be set aside and therefore we support efforts by Enlargement Commissioner Olli Rehn (to solve the problem). The resumption of Croatia's negotiations is in the EU's interests and it is important for the region, the Swedish PM said.