To promote the use of its paid comparison shopping service outside the United States, Google Inc. said today it would offer credits on ads that merchants buy to list products. Merchants who meet conditions can receive 10% monthly credits on those paid listings, called product listing ads.

The offer applies to the following countries where Google is launching Google Shopping: Australia, Japan, Brazil, Spain, Italy, France, the Netherlands, United Kingdom, Germany and Switzerland, according to a blog posting from Sameer Samat, vice president of product management, Google Shopping. In  the United States, Google completed in October its transition to Google Shopping’s paid comparison shopping listings from the free listing offered under the previous service, Google Product Search.  

Google also offered the monthly credit in the United States, for total product listing ad spend through 2012. Merchants in those 10 foreign countries that had set up a Google Merchant Center account—where advertisers load product information and images that appear in the paid listings—by Dec. 1 can apply by April 12 for the credits. Merchants can remain eligible indefinitely for the credits, according to Google’s information page about the program.

“To continue to be eligible for the 10% monthly credit, make sure every product in your Merchant Center account is promoted in a product listing ad campaign,” Google explains.  “This means you should set the campaign’s product target to ‘all products’ and set a bid on the entire campaign.”

Google says it will apply credits to merchants’ accounts. Samat writes that Google expects to complete the rollout of Google Shopping to the 10 countries by the end of the second quarter of next year.