Australian retail giant Woolworths is reportedly in talks to gain part access to the books of rival Coles Group as it mulls a bid for the company.

Local reports said today (20 April) that Woolworths is looking to start due diligence on two Coles' businesses - stationers Officeworks and discount chain Target.

A source close to the situation told Reuters that talks are ongoing but that Australia's competition authorities would allow Woolworths to look at any Coles data outside its core supermarket and liquor operations.

Woolworths is understood to be considering a joint bid with private equity groups. Officials at the retailer could not be reached as just-food went to press.

Two consortiums have officially registered bids for Coles. A consortium led by private equity group KKR plans to at least match a rival offer from a group headed by conglomerate Wesfarmers.

The Wesfarmers-group has tabled an offer for Coles worth A$16.57 (US$13.78) a share or around A$19.7bn.