Police are expecting to use a third camera-equipped robot soon to enter the Pike River Coal mine to gather information.
Superintendent Gary Knowles says police will use a robot sent over from Western Australia.
Mr Knowles says the robot will be able to travel further into the tunnel to take footage, which will be used to plan a recovery of the miners' bodies.
He says the first two robots are still in the mine, though it is not known where they are.