BioWare has announced that publisher EA’s online portal Origin will be required to run Mass Effect 3 for PC – even from copies bought in shops.

Mass Effect 3 will not be available on Steam, but will be available from several other third-party digital distribution services.

“During initial release, Mass Effect 3 will be available on Origin and a number of other third-party digital retailers, but not on Steam at this time,” said BioWare’s community manager Chris Priestly.

“Steam has adopted a set of restrictive terms of service which limit how developers interact with customers to deliver patches and other downloadable content. We are intent on providing Mass Effect to players with the best possible experience no matter where they purchase or play their game, and are happy to partner with any download service that does not restrict our ability to connect directly with our consumers.”

Mass Effect 3 for PC will require a one-time online authentication before it can be played in singleplayer, and there will be no limitation on the number of times Mass Effect can be installed.

Priestly also defended Origin against accusations that it gathered data on users without their knowledge.

“Origin is not spyware and does not use or install spyware on user's machines.”

“In order to allow Origin to install games and their patches for everyone to use, Origin implements a permission change that results in Windows, not Origin, reviewing the file names in the Program data/Origin folder. This is an ordinary Windows function, not an information-gathering process.”

Mass Effect 3 is due on 9th March for PC, Xbox 360 and PlayStation 3.