One of the biggest foreign takeovers in Australian history will force regulators and politicians to weigh who controls critical energy infrastructure against the need to address a looming domestic gas shortfall.

Australia's second-largest gas producer Santos said on Monday it intended to support an all-cash $18.7 billion takeover bid from an international consortium led by Abu Dhabi's National Oil Company (ADNOC),

Santos said XRG, an investment arm of the Abu Dhabi National Oil Company, had made an indicative cash offer of $5.76 a share, valuing the Adelaide-based company at $18.7bn. It represents a 28 per cent premium to Santos’s closing share price last week.