Jakarta – Environment Minister Rachmat Witoelar has blamed excessive construction on water catchment areas for floods which have inundated the Indonesian capital.

Swathes of Jakarta remained under water Saturday as thousands of people forced to abandon their flooded homes spent the night camped out alongside roads and in emergency shelters in higher areas of the city.

Witoelar said excessive construction on natural drainage areas had led to the floods, the state Antara news agency reported late Friday. "There are too many malls in the capital city," he said.

Jakarta has undergone a construction boom recently as the economy recovers to pre-1997 Asian financial crisis levels. The minister said many developers had not paid enough attention to the ecological impact of their construction projects.

Some 13 rivers crisscross Jakarta, with 78 zones considered at risk of easily flooding, including densely-populated districts.

Old Batavia, the former colonial port under the Dutch from where Jakarta has expanded, was built on marshland. Certain areas of the capital still remain below sea level and have weak drainage, with major tides resulting in the outflow of rainwater slowing down.

To improve the situation, authorities have for a long time envisioned constructing an East Jakarta Canal that would be some 24 kilometres (15 miles) long. So far only about a third of it has been built and the city council earlier this month reportedly cut the budget allocated to buy land for the project.