The Dominion Post reports that Archives NZ have found two copies of the tape.
However, the DomPost also say that the tapes are subject to a 70 year restriction imposed by the Transport Accident Investigation Commission, and could not be accessed before 2049 without the commission's approval.
Any request to play the tapes would have to be considered in terms of the law, which is that they can only be used for accident investigation.
I doubt a reopening of the investigation would be considered after all this time