LISBON, Sept 21 (Reuters) - Portugal's government said on Thursday that banks must discount the benchmark six-month Euribor rate by 30% when calculating mortgage interest rates if asked to do so by borrowers struggling to deal with rising interest rates and avoid default. Around 90% of Portugal's stock of 1.4 million mortgages have variable rates indexed to euro interbank offered rates (Euribor) , one of the highest levels in the euro zone. But interbank rates have soared as the European Central Bank hiked interest rates from record lows. "As a result of this measure, the implied interest rate on mortgages cannot exceed 70% of the six-month Euribor rate in the next two years," Finance Minister Fernando Medina told a news briefing. Those with mortgages indexed to three- and 12-month Euribor rates will also receive a discount equal to the nominal amount resulting from the cut in the six-month rate, he added.

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Persons: Fernando Medina, Banks, Medina, Mario Centeno, Association of Portuguese Banks APB, Sergio Goncalves, Andrei Khalip, Kirsten Donovan Organizations: European Central Bank, Finance, Bank of Portugal, Association of Portuguese, Thomson Locations: LISBON