He said it is unlikely that the idle capacity will be used for the NBN because dark fibre is excluded from wholesale regulations.

NBN bidders refused to comment whether Telstra's idle capacity should be used for the network, citing the government's .

A Telstra spokesman said the size and locations of its dark fibre network is commercially sensitive and could not be disclosed.

CEO Sol Trujillo said last week made at the Citigroup Entertainment, Media and Telecommunications conference in Phoenix Arizona, will create problems for the NBN operator.

"It imposes fragmentation of a network so that it creates all kinds of national security issues, it creates customer service issues where nobody has full line of site visibility to end problems and being able to resolve problems," Trujillo said.