LONDON, June 14 (Reuters) - Administrators of the Euribor bank-to-bank lending rate said on Friday that Finland's OP Corporate Bank and National Bank of Greece would join its panel of banks that contribute to the benchmark used in products from mortgages to car loans.

Interbank rates have been trying to repair their reputations after a series of rigging scandals more than a decade ago.

The Brussels-based European Money Markets Institute (EMMI), which administers Euribor, said the two new banks were expected to formally join the current 19-member panel in November once a fresh round of methodology enhancements are finalised.

Revamping the Euro Interbank Offered Rate, as Euribor is officially known, aims to reduce the burden on institutions that provide input by using a standardised approach.

“The enlargement of the panel is a very important step towards maintaining Euribor's long-term sustainability," EMMI’s CEO, Jean-Louis Schirmann, said. (Reporting by Marc Jones; Editing by Alexander Smith)