SINGAPORE (Bloomberg) - Go-Jek, Indonesia's first billion dollar start-up, is looking to expand its ride-hailing services to three to four countries in South-east Asia, escalating its rivalry with Grab and Uber Technologies Inc.

Co-founder and Chief Executive Officer Nadiem Makarim didn't specify the countries or services that Go-Jek will target, but said in an interview they will be places with a large population and where cash rules, hinting that Go-Jek's digital payment service will be a key part of its push into new markets.

Singapore-based Grab, aided by massive funding from SoftBank Group Corp and China's Didi Chuxing, has pushed aggressively into Go-Jek's home turf.

Grab, South-east Asia's largest on-demand transport company, with operations in seven countries, is run by Mr Anthony Tan, Mr Makarim's former classmate at Harvard Business School. For Go-Jek, this will be its first foray outside its home country.

"We've always been on the defensive," Mr Nadiem said in Jakarta, without saying when Go-Jek would expand. "It's time to bring competition to their doorsteps."

After Indonesia, the Philippines, Vietnam and Thailand have the most number of people in the region, with a combined population of about 270 million.

Go-Jek and Grab have rolled out mobile digital payment services, seeing it as a way to scale up their businesses and build a potentially lucrative business by offering financial services to a large number of people with little access to banking.

"I think we've cracked the model of a platform that works in an emerging economy where infrastructure isn't so great," Mr Nadiem said. "There is a high likelihood that we would leverage our full stack. If we come in, we come in with the whole sweep of weapons."