Treasurer Scott Morrison says the decision of the nation’s big four banks to lift their mortgage rates was purely theirs and they shouldn’t blame the government.

ANZ, Commonwealth Bank, National Australia Bank and Westpac have independently increased their standard variable mortgage rates by 0.15 to 0.20 percentage points in the past couple of weeks, blaming regulator-imposed increases in capital reserve requirements.

“I’m not going to give them a leave pass to do that, they can’t blame the government for their commercial decisions, that’s their decision and they need to justify that to their customers,” Mr Morrison told Sydney radio 2GB on Monday.

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In responding to the financial system inquiry chaired by former banker David Murray last week, the government accepted a recommendation that will force banks to retain additional funds to ensure the system remains resilient during difficult times.

But Mr Morrison said the government didn’t force the banks to increase their interest rates.

“A small business out there would have changes to their costs all the time,” he said.

“Now they just can’t run out there and increase their prices because they know it will impact them in how they are trying to make living.”