Corruption costs $1.6tn, UN says

The money is lost in public assets moved across borders via money-laundering or undeclared holdings.

The figure comes as the UN, World Bank and other watchdog meet in Doha, Qatar, to try to give a four-year-old anti-corruption agreement some teeth.

But hopes are low of countries agreeing to independent reviews into countries' finances to look for missing money.

Countries such as China, Iran and Russia are resisting such measures.

Two previous summits have failed to expand the powers of the UN's anti-corruption convention.

"We hope to have a commitment to action," said Ngozi Okonjo-Iweala, a former Nigerian finance minister who is now managing director of the World Bank. "We've had a lot of talk. Now we'd like to see some action."

There is also disagreement over how best to implement the tracking of money, because of tax havens and secretive banking codes in some nations.