Indonesia's president says sinking Jakarta requires giant sea wall

The giant sea wall which is used as a barrier to prevent sea water from flowing into land and cause flooding in Jakarta. Photo / AP

Indonesia's president says he wants to see the speedy construction of a giant sea wall around Jakarta to prevent the low-lying capital from sinking under the sea, lending renewed backing and a sense of urgency to a slow-moving and politically contested mega project.

President Joko Widodo and his government are up against a tight timetable, including a forecast by experts that at the current rate, one-third of Jakarta could be submerged by 2050.

The existential crisis facing the city is the culmination of decades of unfettered development, almost nonexistent urban planning and misrule by city politicians who have served private interests.

Indonesian President Joko Widodo. Photo / AP

Lacking a comprehensive piped water network, industry and homeowners have tapped into the city's aquifers, causing rapid subsidence in northern Jakarta, home to several million people.

In this area, the swampy ground has been sinking at an average of about 10cm a year. Rising sea levels from a heated-up planet will compound the problem in decades to come.

Widodo said it was time to move ahead with the wall, which the government began mulling a decade ago.

"This huge project will need to be done quickly to prevent Jakarta from sinking under the sea," he said.

Women walk near a giant sea wall. Photo / AP

The president said he's determined to push through key projects and reforms in his second and final five-year term, including wanting to build a new capital, suggesting it should be outside Indonesia's main island of Java, where 57 per cent of the country's nearly 270 million people are concentrated.

- AP