Expansion into the new markets will step up the rivalry between Go-Jek and Singapore-based company Grab, which has similar services such as ride-hailing, digital payments and food delivery.
The two start-ups already compete in Indonesia, where Grab is trying to establish a stronghold.
In March, Uber said it was selling its Southeast Asia business to Grab. That strengthened Grab's position in the individual markets across the region.
But Soelistyo said that in light of the recent merger, users and other stakeholders in the new markets would more readily welcome Go-Jek's presence because that would give them a second option to choose from.
"With competition, service offering will be much better, all the players are forced to provide the best customer experience. That will be advantageous for the consumer," he said.
Earlier this year, Google invested in Go-Jek and said the move was in line with the tech giant's ambition to grow Indonesia's digital economy and start-up scene. But Google did not disclose the amount it invested in Go-Jek.
Go-Jek raised about $1.5 billion in a fundraising round in February, exceeding its initial target of $1.2 billion, Reuters reported. The start-up is currently valued at $5 billion, according to private financial market database PitchBook.