TSB and HSBC customers had trouble accessing accounts on Friday after the banks were hit by computer glitches.
TSB said users of its smartphone app and internet banking were having difficulty logging in.
HSBC said about 50% of mobile users had trouble connecting during the morning, although the bank says its problems have now been resolved.
It is the latest in a string of IT outages for the industry, including the recent high-profile meltdown at TSB.
Source: BBC News