Libya's sovereign wealth fund has filed a $1.5 billion lawsuit against Societe Generale, accusing it of funnelling bribes worth tens of millions of dollars to associates of Saif al-Islam, the son of former Libyan leader Muammar Gaddafi.

"Societe Generale contests the unfounded allegations in the Libyan Investment Authority's (LIA) complaint," a spokeswoman for France's second-biggest bank said in an emailed statement, without giving more details.

The LIA said it had filed its lawsuit against the bank in London's High Court.

The LIA alleges that SocGen paid at least $58 million to Leinada, a Panamanian-registered company, for advisory services related to $2.1 billion of derivative trades that the Libyan sovereign wealth fund entered into with SocGen between late 2007 and 2009.

The LIA's legal filing claims that Leinada did not have the expertise to advise or structure such deals.

"The payments were purportedly for advisory support, including around structuring the transactions, though the legal papers highlight that the descriptions of the services provided were deliberately opaque and inconsistent, and the nature and scale of the remuneration was hidden from the LIA," it said.

The LIA said it had suffered heavy losses in the deals with SocGen, and was seeking to have the trades voided to recoup the money allegedly paid to Leinada and to be awarded damages for the alleged fraud.

"This claim, together with the one against Goldman Sachs that was initiated in January 2014, reflects the desire of the LIA's new board of directors to redress previous wrongs and seek the recovery of these substantial funds as it seeks to invest and generate wealth for the people of Libya," the statement quoted AbdulMagid Breish, chairman of the LIA, as saying.-Reuters