Digital platforms like Facebook and Google will be at the centre of an Australian inquiry announced Monday examining their impact on competition in media and advertising markets.

Like elsewhere in the world, traditional sources of circulation and advertising revenues have been drying up for Australian media groups, under siege from the powerful pairing.

Local providers can no longer count on print classifieds to boost income, with digital advertising not yet able to bridge the gap.

With a Morgan Stanley report last year estimating the two online giants will suck up 35-40 percent of the total advertising revenue pool of Aus$13.9 billion in Australia, the government has tasked the competition regulator to probe the impact.