Jakarta. Indonesia will offer the northern Java railway upgrade project first to Japan, smoothing over the last minute snubbing of the East Asian country last year after China was selected to complete Indonesia's first fast rail project.

President Joko "Jokowi" Widodo is in Japan on Thursday and Friday to attend a Group of Seven summit on invitation of Prime Minister Shinzo Abe. The two are expected to meet on the sidelines of the gathering.

Joyce Hutajulu, spokeswoman for director general of railway at Transport Ministry, confirmed the government has prepared a proposal for the northern Java railway upgrade.

"That's to be proposed to Japan," Joyce said on Thursday (26/05).

Under the proposal, the government plans to straighten up some of the railway's sinuous sections and elevate some of the railway crossings over roads in order to allow trains to reach and maintain top speeds of 150 kilometers per hour. Currently, trains rarely reach 100 km per hour.

This will allow travel across the 725 km track between Jakarta and Surabaya to be cut from the current nine hours to below five.

Joyce refused to reveal details of the proposal, including the cost of the project and its term.

Japan would likely compete with familiar rival as China Railway, the national railway operator of the People's Republic of China, had expressed its interest in the upgrading project. Indonesia's Transport Minister Ignatius Jonan agreed to send a team to China to conduct a preliminary study on the project with the company.

It was a deep disappointment to Shinzo Abe after losing Indonesia's first fast train project to China, despite being the first to propose and complete a feasibility study for the project, as well as launching last minutes charm offense to out bid China.

But, Indonesia's refusal to back the project with a government guarantee proved to be nail in the coffin for Japan's fast train proposal.

It remains unclear if the northern Java railway upgrade project will provide such a guarantee.