Shareholders of Hyundai Logistics Co, a unit of South Korean conglomerate Hyundai Group, signed a contract to sell a 600 billion won ($581.45 million) stake in the unit to Japanese financial firm Orix Corp, the group said on Thursday.

The sale of an 88.8 percent stake in Hyundai Logistics will add to Hyundai Group's efforts to raise 3.3 trillion won to improve its debt levels through asset sales and securing investment, the group said in a statement.

Orix and a so-far unknown South Korean partner will pay about 240 billion won for a 70 percent stake in a special purpose company that will own the stake, with the rest held by the group's shipping unit Hyundai Merchant Marine Co, a source with knowledge of the matter told Reuters on Wednesday.