MILAN, July 23 (Reuters) - Carmaker Stellantis said on Friday it had signed a 12 billion euro ($14 billion) revolving credit facility with a group of 29 banks, "available for use in general corporate purposes".

The facility is made up of two tranches worth 6 billion euros each, with three- and five-year maturities, which can be both extended by one year, said the group, formed at the beginning of this year through the merger of Fiat Chrysler and Peugeot maker PSA.

The new facility replaces two existing ones from PSA and Fiat Chrysler, worth a total 9.25 billion euros, providing the group with an increase in its overall available liquidity and an extension of the facility's duration, Stellantis said in a statement.

($1 = 0.8495 euros) (Reporting by Giulio Piovaccari Editing by Mark Potter)