Attending an Olympic forum in Sydney, Coates told delegates that construction had not commenced on some venues, infrastructure was significantly delayed and water quality was also a major concern two years out from the Games.
"The IOC has formed a special task force to try and speed up preparations but the situation is critical on the ground," Coates said on Tuesday in a statement released by the Australian Olympic Commission, which transcribed some of his comments at the forum.
"The IOC has adopted a more hands-on role, it is unprecedented for the IOC but there is no plan B. We are going to Rio."