Bioware have released official details on the Mass Effect 3 multiplayer modes, described as the Mass Effect 3: Galaxy at War system, multiplayer progress will also directly link back to the main single player campaign.
"Featuring four-player cooperative gameplay, multiplayer in Mass Effect 3 puts players in the role of a team of elite Special Forces soldiers sent to protect resources and assets that can help the war effort against the Reapers. Players will have the option of playing as one of six classes and from six different races: Human, Krogan, Asari, Drell, Salarian and Turian."
"The theme of galactic war in Mass Effect 3 presents us with the perfect opportunity to introduce multiplayer into the Mass Effect series," said Casey Hudson, Executive Producer of the Mass Effect series. "Multiplayer not only features amazing combat and deep customization options, but it will give players another way to help the war effort against the Reapers in the main event -- the single player campaign."
The Mass Effect 3: Galaxy at War feature can be activated via an Online Pass code that is found in every new copy of Mass Effect 3, for players who pick the game up second hand, an Online Pass can also be purchased separately on the Xbox 360 and PlayStation 3 - There was no mention of a purchase option for PC, but it is very likely this will exist too.
Mass Effect 3 arrives on the Xbox 360, PlayStation 3 and PC in North America on March 6, 2012 and in Europe on March 9, 2012.