Advertising Age is reporting that Sony is soon to open up its in-game advertising platform sparking a battle for ad space.

The report suggests that Sony will offer an open platform, meaning in-game-ad-serving companies Double Fusion, IGA and Google-owned AdScape will all be able to sell ads in games that run on the PS3.

Ad Age suggests that the three companies will strike deals with the major game publishers creating PS3 games, such as Electronic Arts, Activision and Ubisoft.

It says that the company that wins the best deals with the publishers will win the most space in the already-burgeoning $400 million in-game ad market.

Sony is now starting to sell in-game ads and has its own PlayStation Network salesforce to sell dynamic ads in Sony-produced games.

According to eMarketer data, video game advertising is expected to grow during the next 5 years at a compound annual growth rate of nearly 23%.