FRANKFURT (Reuters) - Opel, the German unit of U.S. automaker General Motors , is close to agreeing to stop production at its factory in Ruesselheim for 20 days this year, German radio station hr-iNFO reported, without saying where it obtained the information.

GM lost $747 million on its European operations last year and would be able to apply for subsidies under the German government's short-work program if management and workers agree to shorten working hours.

The works council still has to approve the agreement, the radio station said.

Under the plan the Ruesselsheim factory, Opel's main plant, would be shut down for 10 days in September after September 6 and for 10 days in October and November, hr-iNFO said.

A spokesman for Opel declined to comment.

The company had said on Monday it was close to signing an accord with workers to cut their hours at the Ruesselsheim and Kaiserslautern plants, without giving details. The carmaker employs a total of 16,500 workers at the two plants.

A pact to shorten the standard workday or week at the two western German plants could be signed within the week, allowing for implementation on September 1, the Wall Street Journal reported on Monday, citing unidentified people familiar with the matter.

(Reporting By Peter Dinkloh; Editing by Helen Massy-Beresford)