By Jemima Garrett for Radio Australia

Papua New Guinea's Prime Minister Peter O'Neill says controversial land leases abused by the timber industry will be cancelled.

PHOTO: Logging companies in PNG are using special agricultural leases to clear vast tracts of rainforest timber. (Supplied: Greenpeace)

PNG's High Commissioner to Australia, Charles Lepani, relayed Mr ONeill's message at the Australian Association for Pacific Studies Conference in Sydney on Thursday.

Mr O'Neill said all Special Agricultural and Business Leases, or SABLs, are under review and that those abused for forestry will be revoked.

A Commission of Inquiry into leases for more than five million hectares of land found that many of the leases were issued without landowners' consent or had legal flaws.

Mr O'Neill said all future large-scale land leases would have to go before Cabinet.

He said an announcement would be made soon.

In 2011 a public outcry over the rorting, mainly by logging companies, of the leasing scheme prompted the PNG Government to set up the inquiry.

Three commissioners were set the task of investigating how 11 per cent of PNG's land mass came to be leased, mostly for 99 years.