"In the frigates case, Switzerland will restitute nearly $266 million to Taiwan," the Swiss justice ministry said in a statement.

The money, it said, "was illegal commissions" paid during a $2.8 billion deal to buy six Lafayette-class frigates in 1991.

That deal, which strained French ties with China at the time, was later found to have been awash with hundreds of millions in bribes.

In 2001, Taiwan requested judicial assistance from Switzerland in the vast corruption case, since much of the ill-gotten money was residing in Swiss bank accounts.

Switzerland had seized some $900 million "as a preventative measure", and in 2005 handed Taiwan numerous documents linked to the accounts.

Two years later, the Swiss restituted a first tranche of $34 million to the Taiwanese authorities.

And on Thursday, the justice ministry said a ruling by Taiwan's supreme court in late 2019 "confirming the illegal provenance of the funds and ordering their confiscation, opens the door to restitution" of another $266 million.

However, it said in a statement, "it has not been proven that the other blocked funds resulted from corruption, and the sequestration affecting them will be lifted."