The Spanish regional leader under fire for his handling of the catastrophic Valencia floods last month has defied calls to step down but conceded that mistakes were made.

The leader of Spain's Valencia region defended his handling of catastrophic floods that killed more than 200 people, saying on Friday he did everything possible in the face of a "monstrous avalanche of water that exceeded all weather forecasts".

The head of the Spanish region devastated by the country's deadliest floods in decades admitted to "mistakes" and apologised on Friday but rebuffed calls for his resignation.

The head of Spain's eastern Valencia region admitted Friday to "mistakes" in handling the country's deadliest flood in decades that killed 216 people there and apologised.