Fergie, centre, performs with sisters Ann, left, and Nancy Wilson, of Heart, at a fundraiser in Los Angeles on April 6. The sisters want Republican Sarah Palin to stop using their 1977 song Barracuda. (Mark J. Terrill/Associated Press)

Rock band Heart has sent a cease-and-desist letter to American vice-presidential candidate Sarah Palin after she used its song Barracuda at the Republican National Convention.

Palin, whose nickname at her high school basketball team was Sarah Barracuda, used the song when she appeared as John McCain's running mate at the convention in St. Paul, Minn. on Sept. 3.

"The Republican campaign did not ask for permission, nor would they have been granted permission," said sisters and singers Ann and Nancy Wilson in a letter about their hit from 1977.

"The McCain campaign respects intellectual property rights," spokesman Brian Rogers told Reuters news agency.

"Accordingly, prior to using Barracuda at any events, we paid for and obtained all necessary licences."

Donating royalties to Obama

One of the song's writers, former Heart guitarist Roger Fisher, said he was "thrilled" with the "ingenious placement of a kick-ass song."

However, he also said he supports the Democratic ticket and would be donating royalties to Barack Obama's campaign.

Under U.S. copyright law, the song is licensed for public performance under a blanket fee paid by the convention's venue.

It marks the second time the Republicans have had a run-in with a musician.

Jackson Browne took legal action last month against the Republicans over their use of his 1977 song Running On Empty in a McCain campaign advertisement which attacked Obama.

A known liberal, Browne performed at concerts to support John Kerry during his presidential race in 2004 and backed John Edwards as Democratic presidential candidate in 2008. He has also donated money to Democratic presidential campaigns.