Auctiva has more than 500,000 users
A third-party add-on for eBay used by thousands of sellers is being flagged by Google as potentially malicious, after it became infected with a trojan.
Auctiva provides tools for sellers on the popular auction website.
The company confirmed a virus had attached itself to files on its servers but remedied the problem soon after.
However, Google continues to warn users searching for the site that it "may potentially harm your computer".
The trojan, called Adclicker, is classed by security specialist Symantec as a "very low risk". It is designed to "artificially generate traffic to certain web sites" and is used by malicious hackers to boost clicks to online banner adverts or to inflate web statistics.
On its community forum Auctiva said that it had "initiated a request with Google to have our site cleared from being reported as a malicious site".
Google works in partnership with the StopBadware.org organisation to warn users about potentially malicious websites that are infected with viruses and trojans.
More than 186,265 websites have been reported to StopBadware for hosting malicious programs or web scripts, which can damage a a computer or, in extreme cases, hijack a machine.
Users first flagged the problem with the Auctiva site last week after anti-virus software began to warn there could be a problem with the service.
Some users reported they were also receiving warnings on auction listings inside eBay.
The firm said it had removed servers in China that had become infected with the trojan and that it was "currently safe to navigate the Auctiva website".
However, until the website is cleared by the StopBadware organisation users will continue to get warnings from Google when clicking on the site following a search.
A spokesman for Google said the site was to be reviewed by StopBadware soon.