Belgian financial investor RHJ International has offered 275 million euros ($387.6 million) for a 50.1 percent stake in General Motors' Opel business, according to RHJ's takeover offer for the German carmaker obtained by Reuters.

The offer, which envisions production cutbacks and pay cuts for staff, sees Opel posting a positive cash flow before funding of 1.0 billion euro by 2011.

Apart from RHJ, Canadian auto parts maker Magna is in talks about taking a stake in Opel, as is Chinese carmaker Beijing Automotive (BAIC).

(Reporting by Gernot Heller, Writing by Nicola Leske)