MTN Group, Africa's largest mobile phone operator on Wednesday posted a 20 percent rise in full-year profit with a strong subscriber growth in emerging markets while revenue rose 2.5 percent to 114.7 billion rand.

Chief Executive Officer Phuthuma Nhleko, who is due to be replaced by Chief Operating Officer Sifiso Dabengwa in March said, "Due to the limited number of opportunities, the board is confident that growth aspirations can be accommodated within the imperative of improved short term returns to shareholders."

MTN is the biggest mobile phone service provider in Nigeria. It's Nigerian unit recorded a 25 percent rise in subscribers to 38.7 million during the period.

MTN is facing increasing competition in Nigeria from Globacom, India's Bharti Airtel and Etisalat.

According to the group which operates mobile phone networks across Africa and the Middle East, its users grew 22 percent to 141.6 million.

Further break down showed a 28 per cent rise in subscribers to 29.7 million in Iran while South Africa recorded growth of 17.3 percent to 18.8 million.

The group said adjusted headline earnings per share totalled 909.1 cents for the year to end-December compared with 754.3 cents a year earlier, at the top end of its own forecasts for an increase of between 18 and 23 percent.

Headline EPS is the main gauge of profit in South Africa, and excludes certain one-time items.

The group declared a final dividend of 349 cents per share, bringing its total dividend for the year to 500 cents. The company has said it aims to return more cash to shareholders as it sees fewer opportunities for acquisitions.