The DLC, titled 'Rebellion', will contain two new maps, three new weapons and six additional character classes, reports Kotaku.
Firebase Goddess shifts the action to the Asari home planet of Thessia, while Firebase Jade is set against the backdrop of a jungle reservoir.
New character classes include Quarian Engineer and Infiltrator, Vorcha Soldier and Sentinel, and the Phoenix Adept and Vanguard.
The DLC was advertised for release today, although the post has since been removed. No mention was made of pricing.
Mass Effect 3's 'Resurgence Pack' was offered for free when it launched last month. It similarly contained a selection of new maps, classes and weapons.
Mass Effect 3 has been heavily criticised for its ending. BioWare has announced that it will release a free Extended Cut DLC pack to "clarify" the ending with additional cinematic sequences this summer.
> Read our review of Mass Effect 3
Watch the 'Resurgence Pack' trailer for Mass Effect 3 below: