Grab, South-east Asia's biggest ride-hailing app, plans to invest US$100 million (S$136 million) in Myanmar as it extends its battle with Uber Technologies to capture the increasing use of smartphones.

Grab will invest the money over the next three years and work with local governments to expand ride-hailing to more cities and roll out services such as GrabPay, its in-app digital payment feature, the firm's president Ming Maa said.

It will grow its workforce in Myanmar about fivefold to 200, he added.

"Myanmar is a very important focus for us,'' Mr Maa said in a telephone interview. "It's a large, rapidly growing mobile-first economy.''

Since its debut in Yangon in March, Grab has grown to reach 25,000 bookings a day with more than 6,000 drivers.

Through its partnership with CB Bank and Wave Money, the company is enabling its drivers to open bank accounts and get access to other financial services in a highly cash-dependent country.

Just six years ago, when Myanmar was emerging from decades of isolation imposed by its military dictatorship, mobile phones were an extravagance available only to the rich and well-connected.

After the launch of telecommunications services in 2014 by Norway's Telenor and Qatar's Ooredoo, almost everyone in Myanmar is now connected.

In 2015, Myanmar signed up more people for mobile phone service than any country in the world, except China and India, countries with much larger populations, according to the Asian Development Bank.

Grab, which made its debut as a taxi-booking app in Kuala Lumpur in 2012, has relied on its mantra of "hyper-localisation'' and massive funding from SoftBank to build its scale and gain an edge on Uber. The United States company began its Yangon service in May.

Singapore-based Grab plans to introduce a corporate travel service in Myanmar, enabling companies to manage employees' local and regional transport expenses digitally, according to Mr Maa.

BLOOMBERG