Australia’s competition regulator, following up on complaints from at least one company last year, is investigating Telstra for anti-competitive practices involving its refusal to offer wholesale access to its 4G network.

The Australian Competition & Consumer Commission (ACCC) has been conducting a preliminary investigation since September to determine if the operator’s actions are anti-competitive and require a formal probe, The Australian reported.

Telstra is the country’s largest mobile operator with a 51 per cent market share and 15.5 million connections, according to GSMA Intelligence. It has 7.2 million 4G users.

Macquarie Telecom reportedly first filed a complaint almost a year ago after Telstra dragged its feet in offering access to its newly deployed 4G network.

The Australian said Telstra committed last year to opening its 4G network to wholesale customers at the start of this year, but last month it backtracked, saying it will offer wholesale access by June 2016. Macquarie also has complained that Telstra will offer rivals 4G services on a different platform with narrower coverage and less functionality.

Industry insiders say that Telstra’s delaying tactics are designed to allow it to expand market share while avoiding moves that would prompt the regulator to take action and set the terms of access. The market leader knows Macquarie, for example, prefers to gain access sooner on terms set by Telstra than having to wait a year or two for the ACCC.

An analyst told Mobile World Live that Telstra will string out the process as long as possible but, of course, fears the regulator being forced to take action.

The Australian quoted a Macquarie representative as saying that Telstra has used its dominant position in the 4G market to delay opening up wholesale access, which had forced some of its business customers to move to Telstra.