Two file-sharing websites claim the new way in which Google is organising its search results will drive more traffic directly to their home pages.
Websites that have been flagged for aiding access to pirated content now automatically appear lower down on Google search lists.
The Pirate Bay and Isohunt both say that Google is not their main source of traffic in any case.
YouTube videos are also subject to the new rules, says the US search giant.
Isohunt's owner had suggested that the Google-owned video clip site would be given preferential treatment because it was excluded from the firm's Transparency Report list of sites that had provoked copyright removal requests.
A spokeswoman for the search giant said: "This update applies to all websites including our own - YouTube, Blogger, etc."
However, since copyright flagging is just one of many factors which influence Google's rankings, it is unlikely that it will have much impact on platforms dominated by user-generated content, such as YouTube, Facebook and Twitter.
Google added that material on YouTube which infringed copyright would be removed from the website completely "in accordance with the law" if it became aware of it.
The new search results are organised according to the number of factors, including the amount of "valid copyright removal notices" Google has received about individual sites.
Those with more notices are likely to appear lower down.
"That Google is putting our links lower is in a way a good thing for us. We'll get more direct traffic when people don't get the expected search result when using Google," said The Pirate Bay in a blog post.
- Arsenal to smash wage structure to Wayne Rooney
- Woman ,21, married to five brothers
- AAR and hospital ‘treated me harshly’ in my hour of need
- New technology could end Kenya’s historic land woes
- Which way for the civil society in today’s Kenya?
- Achebe does not need any foreign decorations, more so in his death