There are numerous versions of Apple's own browser on App Store, but Norway-based Opera is the first rival to get access to iPhone.

Opera applied on March 23 for its mobile browser to be distributed on iPhone, and it was available for downloading to consumers early Tuesday, three weeks later. Usually the review process takes up to one week, developers say.

Analysts have said the decision was difficult for Apple -- whose application store is the only way to distribute software for iPhone users -- as its Internet browsing function is key behind the success of the iPhone.

Opera's browser promises up to six times faster download speeds than Apple's own browser and to cut data traffic by up to 90 percent.

Massive data traffic from iPhone mobile phones has caused problems for many operators' networks.