Takeover target AWE has kicked off the process to give its deal partner Mineral Resources 72 hours to match the 15 per cent higher cash proposal put forward this week by Japanese giant Mitsui amid a flurry of activity around its key gas asset.

AWE's board unsurprisingly determined on Tuesday that Mitsui's 95 cents a share all-cash offer, which values the oil and gas play at $602 million, is superior to the circa 83 cents a share cash and scrip bid from MinRes, the mining services provider controlled by Rich Lister Chris Ellison.