Commonwealth Bank and National Australia Bank are set to cut interest rates on savings accounts by up to 0.25 percentage points in response to last week's reduction in official interest rates, further eroding returns for savers.

CBA, the country's biggest bank, will on Friday announce a drop in the interest rates on at-call savings accounts of between 0.2 and 0.25 percentage points, a move that will be influential in how other banks price deposits.

CBA and NAB are expected to announce cuts to deposit interest rates on Friday. Credit:Josh Robenstone

NAB is also expected to announce cuts in deposit interest rates of up to 0.25 percentage points on Friday.

CBA's popular Netbank Saver account is currently only paying a standard variable rate of 0.5 percentage points — before taking into account the coming cut — a sign of the limits banks will face in trying to cut savings rates further.