Police and former Pike River managers Neville Rockhouse and Doug White are three of 15 groups preparing to have a say before the Pike River Royal Commission holds its final hearings next week in Greymouth.
The commission has received 37 final submissions addressing factual and policy issues. Almost 14 hours has been set aside for the hearings over two and a half days.
The list includes Mines Rescue, Department of Labour, Solid Energy, the Pike River families, and some former directors of Pike River.
After Wednesday, when the hearings end, the commission will work on its report to the Governor General, which is due by September 28.
Mr Rockhouse lost son Ben in the blast.
Mr White was about to leave Pike River when the disaster happened.