TPG Telecom, the country’s third-largest telco, says the number of mobile customers is rising quickly, with a new network-sharing agreement with Optus helping expand its presence into regional areas.

The company, which owns the Vodafone, TPG, iiNet and AAPT brands, reported underlying earnings of $1.98 billion for the 12 months to December 31, a 3.4 per cent rise, helped by a 1.8 per cent increase in mobile customers. TPG had just over 5.5 million mobile customers at the end of the year.