Internet lobbyists say they are worried the German law will set a precedent for other countries such as France and Italy that have shown an interest in having Google pay publishers for the right to show their news snippets in its search results.
Lawmakers in Berlin will debate the bill in the Bundestag (lower house) on Thursday. Google says the law would make it harder for users to retrieve information via the Internet.
Google launched its campaign against the bill on Tuesday with advertisements in German newspapers and a web information site called "Defend your web".
"Such a law would hit every Internet user in Germany," Stefan Tweraser, country manager for Google Germany, said in a statement. "An ancillary copyright means less information for consumers and higher costs for companies."
The campaign has caused outrage among some members of German Chancellor Angela Merkel's center-right coalition.