Hollywood actors will boycott this month's Golden Globe Awards in a show of support for striking writers, the actors union said Friday, dealing a blow to the glittering red carpet extravaganza.

Screen Actors Guild (SAG) President Alan Rosenberg said in a statement there was "unanimous agreement" among actors not to cross picket lines set up by writers locked in a bitter dispute with film and television producers.

Rosenberg said the boycott would cover all nominees up for acting awards in the January 13 event, regarded as the second most important awards show in Hollywood after the Oscars. It would also cover stars acting as presenters.

The decision means that nominated A-listers such as Julia Roberts, Tom Hanks and George Clooney are all likely to steer clear of the Globes, greatly diminishing one of the highlights of Hollywood's awards season.

"After considerable outreach to Golden Globe actor nominees and their representatives over the past several weeks, there appears to be unanimous agreement that these actors will not cross WGA picket lines to appear on the Golden Globe Awards as acceptors or presenters," Rosenberg said.

"We applaud our members for this remarkable show of solidarity for striking Writers Guild of America (WGA) writers."

The head of the Hollywood Foreign Press Association (HFPA), which runs the Golden Globes, said the organisation remained optimistic of reaching a deal with the writers which would allow the show to go on.

"The HFPA has been placed in an extremely difficult position with the ongoing Writers Guild strike," HFPA president Jorge Camara said in a statement.

"We are making every effort to work out a solution that will permit the Golden Globes to take place with the creative community present to participate. We hope to announce a resolution to this unfortunate predicament on Monday."

Hollywood screenwriters have been on strike since November 5 after the WGA and the Alliance of Motion Picture and Television Producers (AMPTP) failed to agree terms for a new contract that expired in October.

Negotiations have foundered over the writers' demands for an increased share of profits from Internet and new media sales.