Ry (RYE) Moran, director of the National Research Centre for Truth and Reconciliation in Manitoba, says thousands of survivors told their stories as part of the compensation process.
The head of the secretariat that co-ordinates compensation claims is arguing that private testimony should be destroyed so it is never made public.
Arguments over the fate of the emotional evidence are to be made before an Ontario judge next month.
Moran says the commission has documents from churches and government, but he adds the oral history of aboriginal people is fundamental.
He says if that testimony were housed in the national research centre, it would be treated with the utmost respect and no survivor would ever be unwillingly identified.