Mubarak has strenuously denied charges he amassed wealth or stashed away funds in foreign bank accounts [AFP]

Switzerland claims it has found $416 million of potentially illegal assets linked to Muammar Gaddafi, Libya's leader, and his circle.

Separately, about $473m traced to Hosni Mubarak, the deposed Egyptian president, and $69mn linked to Zine El Abidine Ben Ali, the ousted Tunisian president, have also been identified, Lars Knuchel, a Swiss foreign ministry spokesman, said on Monday.

"These amounts are frozen in Switzerland following blocking orders by the Swiss government related to potentially illegal assets in Switzerland," Knuchel said.

He declined to name the banks in which the accounts or properties are held.

Mubarak has strenuously denied amassing wealth or stashing away funds in foreign bank accounts.

Both Tunisia and Egypt - where unrest led to the ousting of their respective leaders - are in touch with Swiss judicial authorities regarding their formal requests for legal assistance to seek return of the funds, according to Knuchel.

No such discussions are under way with authorities in Libya, where Gaddafi is clinging to power in the face of an uprising and NATO air raids.

Switzerland, a neutral nation, had previously announced that it was freezing any assets linked to the three north African leaders, thereby requiring financial and other institutions to report any suspicious funds.

Swiss authorities also froze assets belonging to Ivory Coast's now deposed president, Laurent Gbagbo, in January.

Switzerland has worked hard in recent years to improve its image as a haven for ill-gotten assets.

Its cabinet has previously taken blocked funds in accounts held by deposed leaders including Ferdinand Marcos of the Philippines and Nigeria's late Sani Abacha, buying time for foreign prosecutors to build a case for restitution of funds.

Knuchel said that Switzerland had returned $800m held by Abacha to Nigeria, although it took four to five years to complete legal proceedings.

"It was a good example of restitution," he said.

The Swiss finance ministry said earlier on Monday it had started proceedings to return assets of the former Haitian dictator, Jean-Claude Duvalier, frozen since 1986, to the Haitian government.