Alinta has previously said it would sell the Agility operation and management contracts, as well as its units in Australian Pipeline Trust (APT), which it would inherit if its $6.4 billion merger with Australian Gas Light (AGL) goes ahead.

It was seeking to buy enough of APT to gain control of the company.

But the Australian Competition and Consumer Commission (ACCC) said if Alinta were to gain control of APT, it would obtain unacceptable market power in Sydney and Perth.

Alinta has since made a proposal indicating that if it were to buy APT, it would dispose of the trust’s stakes in the Moomba to Sydney (MSP), Parmelia and GasNet Australia Group.

But the ACCC today ruled that under either situation Alinta must sell the Agility contracts.

“The contracts would allow Alinta significant scope for control of the MSP and Parmelia pipelines, even in the absence of any direct ownership and would alter the competitive incentives in relation to the pipelines,” ACCC chairman Graeme Samuel said.

“The ACCC is concerned that ownership of the Agility contracts would give Alinta access to sensitive information regarding the operations of the MSP and Parmelia pipeline.”

The ACCC said it is still assessing the other proposals made by Alinta.

The news comes after the Federal Court on Thursday granted Alinta a stay of the ruling by the Takeovers Panel, which ordered it to sell its 10.25% stake in APT, until October 9.

Alinta is in the process of taking over GasNet, which last week reiterated its recommendation for the $452 million offer.