Iyad Allawi, the head of the Iraqi National Accord, made the revelations to the Arab dailies Asharq Al-Awsat and Al-Hayat on Monday.
He said Saddam "has started to give information on Iraqi money that he invested abroad... which the Iraqi Governing Council estimates at $40 billion placed in Switzerland, Japan, and Germany among others, under fictitious company names."
He added that "Saddam Hussein's trial would not be public since he could name countries and persons whom he gave money".
Aljazeera.net contacted the US authorities in Baghdad to confirm Allawi's comments, but they would only say the former Iraqi president's interrogation is ongoing.
Only a small fraction of the alleged stash has been recovered since US investigators began an international search in April.
A team of experts from the US Treasury and the State, Justice, Homeland Security and Defence departments is searching for the funds in more than 50 countries.
The team is demanding that governments, banks and businesses should reveal the extent of their dealings with the deposed regime and the funds they may be holding.
"(Saddam) has started to give information on Iraqi money that he invested abroad... which the Iraqi Governing Council estimates at $40 billion placed in Switzerland, Japan, and Germany among others, under fictitious company names"
Iraqi Governing Council
Investigators allege Saddam and his family earned a fortune in kickbacks from the sale of Iraqi oil under the United Nations oil for food programme.
They are also thought to have profitted from the illegal sale of oil to Jordan, Syria and Turkey during the sanctions period.
And some analysts allege Saddam and his sons used the Iraqi national coffers to top up their income.
Allawi has also told the Arab papers that questioning of Saddam is now focussing on his relations with "terrorist organisations".
He said: "He has given the names of people who know the location of hidden arsenals used in terrorist attacks against coalition forces and the Governing Council."
Allawi put the number of "terrorists coming from abroad who are carrying out attacks in Iraq" at more than 5000.
He also called for "normalisation of relations between the Governing Council and Arab countries".
"The Iraqi Governing Council has much more legitimacy than some Arab governments. No one should try to compete with us. Don't push Iraq out of the Arab League."