The NPC is China's Communist Party-controlled legislature.
The amendment comes after the People's Bank of China (PBoC), the central bank, announced Tuesday it was cutting benchmark interest rates and would also reduce the amount of funds banks must keep on hand, seen as a bid to boost lending and support China's faltering economy.
The PBoC also announced the elimination of a ceiling on interest rates for time deposits with a maturity of more than one year.
China has been taking steps to liberalise controls on interest rates, which experts see as a key part of further opening up the country's financial system.