Malaysia's aviation authority and British company Inmarsat said Tuesday they would release satellite data used to narrow the search for missing flight MH370 down to the southern Indian Ocean.

Family members of the 239 people on board the Malaysia Airlines plane, which vanished on March 8, had demanded that raw satellite data be made public for independent analysis after an initial undersea search found no wreckage.

"All parties are working for the release of the data communication logs and the technical description of the analysis for public consumption," Malaysia's Department of Civil Aviation and Inmarsat said in a joint statement.

The statement did not say when the data would be made available.

It stressed that satellite data was just one of several elements being examined by investigators.

Malaysian authorities have been tight-lipped on details, saying they can only divulge information once it has been verified and when its release will not affect the ongoing investigation into the plane's disappearance.

Malaysia has said calculations using Inmarsat data showed the Boeing 777 met its fate in the remote southern Indian Ocean after mysteriously diverting from its Kuala Lumpur-Beijing route.

But no sign of the plane has been found there despite a massive and costly search.

Australia, which is leading the hunt in the Indian Ocean, has committed up to Aus$89.9 million (US$84 million) towards the search operation over two years.