Giant telecommunication firm Telstra Corporation is writing down some $138 million in carrying value of its Octave business operation in China, which mainly deals on giving out technical services and providing phone content to mobile platforms.

Telstra currently holds a 67 percent interest in the mobile business, which it acquired for $259 million in February 2009.

According to the statement issued by the telco on Thursday, the impairment charge has been forthcoming as "Telstra highlighted a potential impact on the Octave business in August 2010 following regulatory rulings that were expected to constrain the Wireless Application Protocol market in China."

After four months, that regulation has become more defined and accordingly, Telstra is upgrading its business blueprint for the Octave operations with the consequent result of absorbing "an impairment charge against the carrying value of the Octave investments of approximately $138 million."

Despite the action, Telstra has maintained that Octave's business guidance remains in line with earlier projections as they "explicitly excluded asset impairments and proceeds from asset sales."

Also, Telstra revealed that its other business interests in China are performing within expectations as it reported that "Sequel and LMobile continue to perform well."

In other company development, Telstra announced too the departure of Nerida Caesar as its group managing director of enterprise and government and would be replaced by current group managing director of Telstra Wholesale, Paul Geason.

A separate statement from the company simply stated that Caesar would leave by early next year to pursue another career opportunity and Geason's assumption to his office would push up Glenn Osborne, presently executive director of Telstra Wholesale Sales, as head of the company's wholesale division, though in a provisional capacity.