Once users had logged on to the site, the software claimed the HTLM-Agent-CE Trojan had been installed onto their PC.
HSBC told ZDNet that the site had not been attacked and that "the latest update to Kaspersky AV software is generating messages on some secure websites (including ours) when none is warranted".
Meanwhile a Kaspersky spokesman told The Register the warning was false and the problem had been "rectified quickly".
No other security vendors have reported that HSBC's site was infected.
See also: Kaspersky launches Linux antivirus