Indonesia has finalised its plan for a national railway network, which as envisioned by President Joko Widodo, will beef up land connections and support all seven of its key seaport hubs.

The network will also include a separate circle line around Bali to offer better access to untapped parts of the resort island where new tourism developments can be built.

With more than 3,200km of train tracks that will criss-cross the islands of Sumatra, Java, Kalimantan, and Sulawesi, it has been touted as the most extensive railway project in Indonesia since its independence from the Dutch 72 years ago.

Once completed, the project is expected to not only drive trade and economic growth, but the government also hopes the improved inter-connectivity will lower inequality in less developed regions.

"Our economy needs to grow with equality, and we want to avoid disparity across the country, and building a railway network would help to address this issue," said Mr Wismana Adi Suryabrata, deputy chief for infrastructure at Bappenas, the national development and planning agency.

Mr Joko has been pushing for infrastructure development as part of a broader plan to grow Indonesia's economy, which is expected to expand by 5.2 per cent this year, and 5.4 per cent next year.

Mr Wismana said the railway plan - which will move both people and goods - will complement existing sea lanes and toll roads, and offer more seamless transportation links between cities, towns as well as industrial and tourism areas. "The railway, toll roads and ports will eventually be interconnected with the seven international and domestic port hubs," he added.

The seven ports are Kuala Tanjung (North Sumatra), Batam (Riau Islands), Tanjung Priok (Jakarta), Tanjung Perak (Surabaya), Makassar and Bitung (Sulawesi), as well as Sorong (West Papua).

"Another reason for the strategy is to grow the tourism sector," added Mr Wismana. "We have identified 14 industrial zones for priority development, but we also want to create 10 new 'Balis', or 10 new tourist destinations."

But Bali will also receive a boost under the new plan with a possible railway that goes around the island, The Straits Times has learnt.

Mr Atmadji Sumarkidjo, a senior official from the Coordinating Ministry for Maritime Affairs, pointed to areas in north Bali, where the lack of access has slowed growth.

"They have already built cottages there but without connectivity, the occupation rate has been low," he added.

"So with the northern part relatively deserted, compared to the packed southern parts of Bali, connecting north and south of the island by rail is a good solution."

Not all of the railway lines will be built at the same time, said Mr Wismana, when asked about the project's timeline.

He added that Jakarta will have to work with local governments to establish demand and thereafter prioritise its funding for the project.

Mr Joko's infrastructure development plan will require about US$360 billion (S$492 billion) in investments between 2015 and 2019 - the term of his presidency - from the state as well as other partners.

The ambitious proposal for the national railway network comes amid recent news that the cost of the Jakarta-Bandung high-speed rail (HSR) has swelled to almost US$6 billion, from US$5.2 billion.

Jakarta, however, remains confident that the 142.4km rail project, which is 75 per cent funded by the China Development Bank, is still on track to be completed by 2019.

Analysts welcome the rail masterplan, saying that too much focus has been placed on the HSR project, which serves only Jakarta and Bandung, while a national rail infrastructure has been slow to materialise.

An earlier version of the plan has been hit by funding issues, with the government managing to lay only about 200km of new railway tracks between 2015 and last year.

This represents just 6 per cent of the 3,258km of railway to be built from 2014 to 2019 in Sumatra, Sulawesi and southern Java.

Still, observers say Mr Joko must push on with the national rail project, which was part of an ambitious infrastructure development promise he made to voters during his election campaign in 2014.

"All the attention has been just on the high-speed railway linking Jakarta and Bandung, and not enough attention on how to help build the economy of other cities or regencies," said Mr Nirwono Yoga, an urban planning expert from Trisakti University in Jakarta.

"There has to be a plan where its development benefits all."