Australia’s largest operator Telstra said an investigation which could mandate national roaming in rural areas would hurt competition and slow investment.

The Australian Competition and Consumer Commission (ACCC) announced today it was studying whether to create a wholesale national roaming regime, which would mean operators would need to share their mobile networks with rivals.

This is the third time the agency has looked into wholesale roaming. The last inquiry was in 2005. quoted Tony Warren, Telstra’s head of corporate affairs, as saying: “Declaration would ensure there is no incentive for any operator to invest for competitive reasons in many regional areas. In contrast, history shows that when declaration is ruled out, investment flows for regional Australians.”

“Declaring mobile roaming would stop coverage being a differentiator in the Australian market and, therefore, remove the key rationale for investment in regional Australia for all operators,” he said in a statement.

The inquiry will focus on “whether there are differences in regional areas to urban areas” and the likely investment plans of operators to extend coverage and upgrade technology, without a declaration being issued.

ACC chairman Rod Sims noted that, at this stage, it has not formed any views on whether a declaration of mobile roaming service would deliver benefits for customers. “A particular area of concern for us is whether consumers could be disadvantaged if the incentives to invest in expanding the reach of mobile networks were reduced.”

He noted, however, that there has been significant interest around access to mobile networks and mobile roaming, including from representatives from regional Australia, the Regional Telecommunications Review Committee, Infrastructure Australia and the House of Representatives Agriculture Committee.

A month ago the ACC said it was conducting a market study of the country’s communications sector to examine a range of issues concerning competition and efficiency. Sims said ACC considered examining roaming issues as part of the study, but it decided that a “more focused inquiry to deal with the issue more quickly will provide the market with greater certainty, sooner”.