Kerry Stokes' Seven Group Holdings has emerged as a thorn in the side of Mitsui, creating a real risk that the Japanese trading giant may fail to secure total ownership of AWE in its $602 million takeover bid.

Seven, which is allied with AWE's partner in the prized Waitsia gas field in Western Australia, Beach Energy, is understood not yet to have accepted Mitsui's offer for its circa 4 per cent stake as it considers its options and monitors acceptances of the offer.