The announcement of charges followed a five-year investigation into whether Google's preferential use of its own shopping product in its search engine could be harmful to consumers and competitors.
"We asked the European Commission for extra time to examine documents that they have given us. They put back the deadline until August 17," spokesman Al Verney said.
Google accounts for 90 percent of the online search market in Europe.
The EU is concerned that Google's retail competitors like travel portal TripAdvisor or business review site Yelp could be squeezed out as a result of Google's dominance.
The California Internet company could face huge fines if found culpable, as much as 10 percent of its $66 billion (59 billion euros) in worldwide turnover last year.