Telstra will have to provide reasons for denying competitors access to exchanges after the Australia Competition and Consumer Commission (ACCC) ruled it must show detailed records of DSL provisioning.

The mandate comes after a series of complaints from Internet Service Providers (ISPs) that claimed Telstra was denying access to its exchanges due to "insufficient space" and long delays with its queueing system.

Competitors say the delays are preventing them from deploying ADSL2+ services.

The announcement comes days after the ACCC launched an arbitration process between Telstra and NEC Australia regarding the incumbents' provision of Line Sharing Service (LSS). The higher frequency bands of a line can be used to provide DSL services while the lower spectrum is used for PSTN voice services.

ACCC chairman Graeme Samuel said a large number of competitors filed complaints to the regulator regarding Telstra's refusal to provide access to its exchanges.

"The ACCC believes that there is a strong need for independent oversight of Telstra's processes to cap exchanges to ensure that Telstra is held accountable and access seekers are not unreasonably denied access to Telstra exchanges," Samuel said.

"There is also a clear need to identify the exact cause of delays with Telstra's queuing system.

"The record keeping rule will assist the ACCC in carrying out its statutory functions under the access regime in the Trade Practices Act and provide confidence to access seekers investing in competitive DSLAM infrastructure about the accuracy of Telstra's processes."

The telco will need to supply monthly access reports to the ACCC detailing its reasons for restricting access to exchanges and the amount of space it allocates to itself.

It will also be required to publicly reveal its queueing lists of access seekers, their position and progress through the lists.