Last week Alinta entered the bidding race with a estimated $1.7 billion offer backed by Macquarie Bank and AMP with a plan to refinance the deal later by introducing the soon-to-list DUET. The end result would see Alinta holding a 10% stake, AMP/Macquarie 80% (through DUET) with the final 10% provided by another of the pipeline’s major customers.

Alcoa has a vested interest in a prompt sale of the pipeline and its expected expansion so it can secure the additional gas capacity required for the proposed expansion of its South-West alumina operations.

The consortium is understood to be planning to spend up to $500 million over three years expanding the pipeline's capacity.

The State Government has sought to encourage a successful outcome by effectively waiving a stamp duty bill of up to $110 million on the pipeline sale. However, the entry of the pipeline’s major carriers in to the bidding race has not gone down well with several competing groups.

Representatives of the three confirmed bidders, Australian Pipeline Trust, Envestra CKI and Prime Infrastructure claim that it will be impossible to come to commercial terms with Alinta if it remains as a competitor in the bidding process.

Adding to the drama is Alinta’s alleged lack of access to the pipeline’s data room due to reasons of commercial confidentiality, which led to the company’s withdrawal from the bidding process earlier this year.