Commissioner Paul Belanger says the date still depends on completion of construction of the inquiry's hearing room.
He also says the commission will have to have all the documents it needs.
In a letter to residents of Elliot Lake, Belanger says his team is working "at full speed" to gather the required information and documents.
The inquiry is delving into the collapse of the Algo Centre Mall last June that killed two women.
It is also looking into the emergency response that followed.
"We have so far received approximately 280,000 documents and my team is diligently reviewing, categorizing and classifying them," Belanger said in his letter.
Commission investigators have also interviewed about 250 people.
The public hearings will be broadcast on the Internet.