Users will click on an advertiser's sponsored link and then be offered the chance to enter their own telephone number, before the advertiser is contacted and a call made back to the user.
Miva, the online performance marketing company, has a similar service, but questioned what it sees as a potentially lengthy process in order to make contact with the advertiser.
Miva said this week that it welcomed the addition of another new pay-per-call service to the market, as an "awareness raising" exercise for the model for consumers, but it believed the Google system would provide too many barriers to the user.
Seb Bishop, director and chief marketing officer for Miva, said: "The web is all about instant gratification and we question how effectively a call-back-style model meets this demand", Media Week reports.
