Vietnam's Viettel Global and Myanmar's state-backed Yatanarpon Teleport are awaiting approval for an investment of at least $800 million to build Yatanarpon's telecoms infrastructure in Myanmar, officials from both companies said on Friday.

Myanmar - where communications were tightly controlled by the former military junta - is one of the world's last telecoms frontiers, with just a small minority of the 53 million population having a mobile phone.

Last month Viettel Global, the investment arm of Vietnam's military-run Viettel Group, announced plans to contribute $800 million to developing telecoms with an unnamed partner in Myanmar, and told Reuters on Friday it will likely announce the decision of its shareholders on Dec. 15.

An official in Hanoi with direct knowledge of the negotiations confirmed that Yatanarpon was the Myanmar partner.

Yan Win, a member of Yatanarpon's board of directors, told Reuters the board had finalised talks with Viettel and was waiting for Yatanarpon's management to approve the deal.

The total investment for the deal will rise to between $1.8 and $2 billion, said the official in Hanoi who declined to be identified because he is not authorised to speak to the media.

Viettel Global said the additional funds would be raised by its foreign partner and a joint venture, to be established by both firms, the Vietnamese company said in the plan published in November.

Aung Tha, CEO of Khine Thit Sar, a Yangon-based company helping to upgrade the state-owned Myanmar Posts and Telecommunications (MPT), said he was aware of talks between Viettel and Yatanarpon, which has primarily been an Internet service provider until now.

"It will be tough for them to compete with the existing operators," he said. "They have no infrastructure, they will have to start from scratch."

Swedish telecoms giant Ericsson said that in 2012 less than 4 percent of the country's population had mobile phones.

That number has risen dramatically over the past few months as Norway's Telenor and Qatar's Ooredoo have begun selling SIM cards after the reformist government, which took power in 2011, granted the companies telecoms licences.

MPT, formerly the country's sole provider, has also scaled up distribution of SIM cards and has partnered with Japanese firms KDDI Corp and Sumitomo Corp, which have said they will invest $2 billion.

Yatanarpon reportedly holds the fourth telecoms licence and its chief executive told Reuters last year that it would seek at least $1 billion from investors to expand its operations.