Telco giant, Telstra, is continuing to boost its mobile growth, adding 1.3 million domestic retail mobile customers during the 2013 financial year.

Net profit after tax increased 12.9 per cent to $3.9 billion and a total income increased 1.9 per cent to $26 billion for its 2013 financial results, ending June 30.

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It now has 15.1 million mobile customers and its mobile revenue grew six per cent to $9.2 billion.

Telstra CEO, David Thodey, said the result was an endorsement of Telstra's strategic direction.

"Our strategy around improving customer service, as well as focusing on our growth businesses is working. I am pleased that we have once again delivered on our commitments and met our guidance, at the same time as continuing to simplify our business," he said.

"We know our customers value extensive coverage, fewer drop outs on calls and reliable mobile data speeds and we invested $1.2 billion in our mobile network during the year to deliver on this.

"This investment includes expanding the reach of our 4G network which now covers 66 per cent of the population and is on target to reach 85 per cent by the end of the year."

He mentioned that Telstra's 4G network build accelerated during the year, and since launch, the company has activated more than 2.8 million 4G devices.

The telco plans to continue to build momentum in its Network Applications and Services (NAS) portfolio.

NAS revenue increased 17.7 per cent to $1.48 billion for the year and included the commencement of a $1.1 billion, six year contract with the Department of Defence, as well as international agreements with Jetstar and Fitness First.

"Part of the NAS growth strategy is to expand into international markets, particularly in the Asian region and there are discussions underway regarding the establishment of delivery centres in conjunction with industry partners located in India," he said.

Its international businesses, comprising the Hong Kong mobile services (CSL New World) business, the Telstra global connectivity and NAS business and the China digital media businesses, saw revenue growth by 16.2 per cent to $1.73 billion.

However, its Australian media revenue, which includes Sensis, declined by 7.8 per cent.

"Sensis continues to be restructured as it transitions from a print to a digital business," Thodey claimed.

He added that Telstra expects growth to continue in the financial year 2014 and forecasts low single digit total income and EBITDA growth, with free cashflow between $4.6 billion and $5.1 billion. Telstra also expects capital expenditure to be around 15 per cent of sales as it continues to build out its 4G mobile network.

"Our strategic focus remains on improving customer satisfaction, growing our customer base, simplifying the business and finding new growth opportunities. We believe there remains further opportunity to improve operational efficiency while at the same time growing new business opportunities," Thodey added.

It also stated a $0.14 fully franked dividend bringing the total dividend to $0.28 per share for its financial year 2013, a return of $3.5 billion to shareholders.