Google is rejigging millions of search results to allow rival shopping-comparison services to bid for and resell advertising space at the top of Google search results in Europe.

The new ads appear alongside similar product ads from Google’s own shopping-ad unit.

The changes are part of the search giant’s effort to comply with a European Union anti-trust decision that fined the company a cool 2.42 billion euros (A$3.6 billion) for using its dominant search engine to favour its own shopping ads at the expense of competitors.

Google, which is still appealing the decision, is implementing the order to avoid noncompliance fines that can reach more than $12 million.