Indonesia is scrapping a US$6 billion (S$8.5 billion) plan for a high-speed train because it is not commercially viable and is asking bidders China and Japan to submit new proposals, Bloomberg reported.

The government of Indonesia now wants a slower train capable of travelling at 200 km per hour between the capital Jakarta and the third-biggest city Bandung, the minister coordinating policy for transport, Rizal Ramli, told Bloomberg News on Thursday.

The need for new proposals, which could be 30 per cent to 40 per cent cheaper, will delay the decision by several weeks, he said in his first interview with international media since taking office last month.

China and Japan have been lobbying Indonesia's government for the contract for a high-speed train, which would be the biggest infrastructure project started by President Joko Widodo. The president, who took office last year vowing to overhaul railways and ports in the world's largest archipelago, has made little progress.

"We don't need a high-speed train but a medium-speed one," Ramli said after meeting other ministers. "Japan and China are competing very hard, we should let them compete to the maximum."

Indonesia wants to develop places on the route to Bandung and a medium-speed train with more or lengthier stops would achieve this better than a high-speed train, Ramli said.

The route should also be linked with a light rail project through Bandung's city centre to avoid travellers zooming to the city and then getting stuck in its traffic jams.

(With inputs from Bloomberg)