WARSAW, May 11 (Reuters) - Poland’s Supreme Court has delayed announcement of its guidelines on how courts should treat cases concerning foreign currency loans to ask for opinions from institutions including the central bank and the financial regulator. The institutions have 30 days to give the court their opinions, but court spokesman Aleksander Stepkowski said there was no fixed date for when the court would announce its decision. Reporting by Alan Charlish, Pawel Florkiewicz, Anna Koper, Anna Wlodarczak-Semczuk Editing by David Goodman Our Standards: The Thomson Reuters Trust Principles.