Tatts Group’s plan to form an Australian betting behemoth with rival operator Tabcorp Holdings is being challenged yet again.

This time, the Pacific Consortium—a group backed by U.S. private equity firm Kohlberg Kravis Roberts (KKR)—has returned to present a multi-billion-dollar spoiler to the planned merger between the two Australian gambling operators.

Australian Securities Exchange-listed Tatts confirmed on Wednesday that it had received a A$7.2 billion (US$5.4 billion) takeover bid from the consortium, consisting of KKR & Co, Morgan Stanley, Macquarie Group, and First State Investments.

The new proposal offers A$4.21 (US$3.17) per Tatts share and may include a A$0.25 per share special dividend, which will be paid immediately prior to any deal being implemented. The consortium’s offer is all-cash, which does not require regulatory approvals.