Although the company’s interest had never progressed to a formal offer the bid backed by investment bank Babcock & Brown was widely reported as being prepared to pay $1.7 billion for the key WA asset.

Prime removed itself from the race after spending $1.6 billion on a controlling interest in New Zealand energy utility Powerco, which meant it would be unable to enter a firm bid by the August 27 deadline.

“On completion, it will increase Prime Infrastructure’s gross underlying asset value to around $3 billion and strengthen our position as a major participant in the Australian and New Zealand infrastructure industry,” said Chris Chapman, managing director of Prime Infrastructure Management.

“With the Powerco acquisition Prime Infrastructure will have completed more than $2 billion in acquisitions since listing.”

Of the three bidders left Australian Pipeline Trust and Envestra continue to voice their disapproval of Alinta’s last minute bid, claiming that as one of the pipeline’s major carriers the energy utility may have an unfair advantage in negotiations and could be in breach of the Trade Practices Act.

In reply Alinta said it is planning a separate management and board to operate the pipeline in an attempt to overcome and conflict of interest or monopoly concerns.

However Alinta has now been joined in its bid by Alcoa, which is keen for immediate expansion of the line so as to ensure supply for the proposed expansion of its Wagerup alumina refinery.

The consortium is now attempting to negotiate tariff arrangements with the pipeline’s major shippers which justify a bid close to the $1.85 billion in bank debt owed by Epic.