Uzbekistan on Wednesday called for more international help over the shrinking of the Aral Sea, after recent images showed part of the lake had dried up completely.

In an environmental catastrophe that haunts Central Asia, the Aral Sea on the border of Uzbekistan and Kazakhstan has been ravaged due to Soviet irrigation projects dating back to the 1960s.

Last month NASA said satellite imagery showed that the southern basin of the lake, once the world's fourth-largest inland body of water, had completely dried up "for the first time in modern history".

Veteran Uzbek President Islam Karimov called on an international conference of experts and donors to come up with more aid to counter the devastation caused by the disappearance of the lake.

"The countries of the region do not have sufficient funds and logistical means to overcome the environmental, socio-economic and humanitarian consequences of the disaster," Karimov wrote in an appeal.

"Today the Aral Sea is on the verge of extinction. This loss will affect the lives of millions of people in Uzbekistan and abroad," UN chief Ban Ki-moon said in a video address.

The desiccation of the Aral Sea is considered by some experts to be the worst man-made ecological catastrophe ever, in a region where tensions have already flared over sharing water resources.

It also has had huge implications for human wellbeing.

Fishing and other shoreline industries that once thrived have been destroyed. Each year, tens of thousands of tons of salt-laced dust blow from the dried-up seabed, much of it contaminated by pesticides, affecting health.