MELBOURNE - Rio Tinto apologised to an Australian parliamentary inquiry in its submission on Tuesday for the destruction of ancient sacred caves, admitted to numerous errors, and said it supported reforms to state heritage laws.

The world's biggest iron-ore miner in late May legally destroyed two historically significant sacred caves in Western Australia state, against the wishes of the Traditional Owners, but that sat atop a high grade ore body it planned to mine.

The destruction distressed the local Puutu Kunti Kurrama and Pinikura people (PKKP) and fuelled a wider public outcry that led to a Senate Inquiry into how the blast was legally sanctioned, which Rio's chief executive will front on Friday. “The destruction of the Juukan rockshelters should not have occurred and I have unreservedly apologised to the Puutu Kunti Kurrama and Pinikura people," Jean-Sébastien Jacques said in a statement.

"As a first priority our aim is to strengthen our partnership with the PKKP....We have also taken actions to strengthen governance, controls and approvals on heritage matters."

Rio had received approval under state heritage laws to destroy the culturally significant sites in a process that does not allow Traditional Owners the right to appeal, or for approval to be withdrawn even if excavation uncovers significant artefacts.

In its detailed submission, Rio said that it believed it had the consent of the PKKP but acknowledged it had missed opportunities to convey the extent and timing of the destruction of the caves.

By the time the PKKP had expressed their explicit desire to halt the process in May, explosives had already been set, Rio said.

"It is clear that various opportunities were missed to re-evaluate the mine plan," Rio said.

Rio also said that it would support a process in the state's heritage act that would allow Traditional Owners to appeal a decision to destroy a sacred site. The laws are under review, and expected to be tabled before year end.