AMSTERDAM (Reuters) - Dutch financial services group ING <ING.AS><ING.N> is negotiating the sale of its car leasing business in a deal potentially worth 4 billion euros ($5.7 billion), a Dutch newspaper reported on Monday.

Citing sources familiar with the bank's divestment plans, newspaper Het Financieele Dagblaad said ING, which has been selling assets to boost its balance sheet, has been negotiating the sale of its car leasing business for months.

ING was not immediately unavailable for comment.

ING's Car Lease division is not on the list of disposals agreed by ING with the European Commission as part of a restructuring program forced on the group as a condition of its 10 billion euro state bail-out during the financial crisis.

The newspaper said car leasing peers including BNP Paribas' Arval <BNPP.PA>, Rabobank <RABN.UL> subsidiary Athlon <ATHLG.UL>, BMW-Alphabet <BMWG.DE>, Volkswagon <VOWG_p.DE> and GE Fleet Services <GE.N> have been approached by ING's advisory banks to discuss a potential deal.

Last week Capital One Financial Corp <COF.N> agreed to buy ING's U.S. online bank for $9 billion in cash and stock, freeing the Dutch bank to repay bailout funds and sever its state ties.

(Reporting by Roberta B. Cowan; Editing by David Holmes)