Australia’s competition watchdog called for additional comments from stakeholders into its preliminary view of a proposed spectrum sharing agreement between Telstra and TPG Telecom, after failing to sate initial concerns.

The Australian Competition and Consumer Commission (ACCC) stated it remained concerned high concentrations of spectrum holdings might deter incumbents from offloading surplus licences and instead incentivise them to prevent others accessing it.

It explained to grant authorisation, it must be satisifed the transaction would not substantially lessen competition, or ensure the benefits to the public outweigh any downsides.

The agency is reviewing an application for the acquisition of certain TPG Telecom spectrum tied to three interrelated network agreements which are being considered together.

“We are looking extremely closely at all aspects of these agreements, as a decision either way can have significant long-term effects”, ACCC commissioner Liza Carver stated.

Carver explained the ACCC is assessing how the proposed infrastructure and spectrum arrangements will change the incentives and ability of Telstra, TPG Telecom, Optus and others to compete and invest in mobile infrastructure.

“There is still a lot of work to do on this complicated and nuanced review.”

“At this stage we have not reached any overall conclusions, but welcome further submissions from stakeholders and consumers alike on the issues raised.”

Submissions are due by 14 October. A decision is likely be announced in early December.

The ACCC estimates the arrangement to actively share mobile infrastructure in certain regional and urban fringe areas covers about 17 per cent of Australia’s population.

Rival Optus called for the regional element to be rejected.