Courtney Love is a leading campaigner against the contacts

The senator is working on behalf of musicians such as Courtney Love, LeAnn Rimes and Don Henley, who have lobbied the California state legislature saying such contracts are unfair and a form of "indentured servitude".

Under current US law, record companies have a special exemption allowing them to sue musicians and singers for albums not produced over the course of seven-year contracts.

'Scoff'

Senator Murray said artists should take their cue from the powerful Recording Industry Association of America (RIAA) trade group and learn to lobby Congress.

The only way record companies can continue to invest in new talent is if successful artists live up to their agreements

RIAA statement

"The RIAA is very effective. Rather than scoff at it, I would suggest that artists use it as a model," he told the gathering of musicians, media executives and lawmakers in Washington.

He added it was the industry's clout that got the amendment passed in the first place.

Executives from nine record companies sent a letter to Murray on Monday opposing the proposed repeal of the amendment.

'Talent costs'

They said they conduct their business fairly and that artists benefit from the contracts they sign voluntarily.

"The recording industry is making huge and escalating investments in marketing, promotion and talent costs for new artists (in amounts now exceeding $1bn each year)," said the letter, signed by such industry heavyweights as Sony Music chief Thomas Mottola, Universal Music chief Doug Morris and Warner Music chief Roger Ames.

"But less than 10% of the recordings released each year are able to generate a profit. The only way record companies can continue to invest in new talent is if successful artists live up to their agreements," the letter said.

The campaigning artists have formed a group known as the Recording Artists Coalition and have the backing of stars, including Elton John, Billy Joel, Sheryl Crow and the Eagles, who are planning several concerts in Los Angeles before the Grammys to raise money and awareness for their crusade.