A Canadian hard-rock band says it sent the Pentagon a $666,000 bill after a former Guantanamo Bay guard alleged that the US military used their music to torture detainees.

Skinny Puppy found out their music was blasted out at the detention center in southern Cuba from a former guard who is a fan of the band, keyboardist Cevin Key told Canada's CTV Television.

Rights groups say that prison officials subjected Guantanamo's terror suspects to "deafening loud music," often featuring violent lyrics, during interrogation.

Several other bands, including REM, Rage Against the Machine and Metallica, have denounced the use of their music at Guantanamo.

"We sent them an invoice for our musical services considering they had gone ahead and used our music without our knowledge and used it as an actual weapon against somebody," Key told CTV.

The amount they requested may be a reference to 666, known as "the devil's number," in light of the band's Gothic themes.

But the Pentagon said it had not received any invoice from the band.

"One wonders how such a bill might reasonably be generated and lawfully delivered, based on an unsubstantiated claim by some random, nameless fan, as one member of the band alleges, or via 'grapevine,' as another member of the band alleges," spokesman Colonel Todd Breasseale told AFP.

And he suggested the claim was a ploy by Skinny Puppy to garner free publicity.

"Kudos to them though, for garnering this much free press and circular reporting around the time of what one news source says is the launch of a new album and another says is the launch of a tour," the spokesman added.

The group, which has a cult following, has performed live with band members smeared in fake blood, sporting machetes, animal skins and heavy black and white makeup. They have even included mock executions in their performances.

Key said band members were "offended" to learn the claims that their music was played at Guantanamo to "inflict damage" on detainees.

"I wouldn't want to be subjected to any overly loud music for six to 12 hours at a time without a break," he said, acknowledging that Skinny Puppy's music could be a "terrible nightmare" for some listeners.

Breasseale, the Pentagon spokesman, stressed that the use of sleep deprivation and sensory manipulation was not authorized by the Army Field Manual, and prohibited by law.

"The futility approach in Army Field Manual 2-22.3 does not authorize the use of loud music. We simply do not use it," he added.