The responsibility has been assigned to a Melbourne based developer by the name of Straight Right. They previously have worked on the iOS version of Shift 2: Unleashed.
The developers confirmed this news on their Facebook page saying:
Happy to confirm that we’re developing Mass Effect 3 for Wii U with our friends at BioWare!.
Mass Effect 3 is one of the main launch titles for Nintendo’s upcoming console Wii U. The third sequel in BioWare’s Mass Effect universe has gotten the respect of many players from around the world.
Let’s hope Straight Right does justice to the Wii U port of Mass Effect 3.