A report released this week by the Recording Industry Association of America said it found Google's initiative announced last August to "demote" sites accused of piracy appeared to be having little or no effect.
"We have found no evidence that Google's policy has had a demonstrable impact on demoting sites with large amounts of piracy," said the RIAA report released Wednesday.
"These sites consistently appear at the top of Google's search results for popular songs or artists."
The RIAA said it analyzed "serial infringers" identified in Google's Copyright Transparency Report "were not demoted in any significant way in the search results and still managed to appear on page one of the search results over 98 percent of the time in the searches conducted."
It added that the questionable sites "consistently showed up in three to five of the top 10 search results."
"We recognize and appreciate that Google has undertaken some positive steps to address links to illegal music on its network," said RIAA general counsel Steven Marks.
"Unfortunately, our initial analysis concludes that so far Google's pledge six months ago to demote pirate sites remains unfulfilled. Searches for popular music continue to yield results that emphasize illegal sites at the expense of legitimate services, which are often relegated to later pages. And Google's auto-complete function continues to lead users to many of those same illicit sites."
Responding to the RIAA, a Google spokesperson said, "We have invested heavily in copyright tools for content owners and process takedown notices faster than ever."
Google said that in the last month "we received more than 14 million copyright removal requests for Google Search, quickly removing more than 97 percent from search results."
Last August, Google said it was tweaking its search formula to give higher priority to legal content and sink rankings for websites hit with piracy complaints, which focus on illegal copies of music, films and other content.
More than 200 "signals" are factored into Google's secret search algorithm for determining what gets priority on results pages.