MOSCOW - A jailed member of Russia's Pussy Riot punk band said she was starting a hunger strike on Monday to protest against "slave labour" in her penal colony and said she had received a death threat from a senior prison official.

Nadezhda Tolokonnikova was sentenced to two years in jail in August 2012 after performing what the band called a "punk prayer" in a Moscow cathedral in a protest against President Vladimir Putin amid mass street protests against his rule.

"Beginning September 23, I am going on hunger strike and refusing to participate in colony slave labour," Tolokonnikova wrote in a letter circulated by her husband Pyotr Verzilov.

"I will do this until the administration starts obeying the law and stops treating incarcerated women like cattle," she wrote.

Tolokonnikova is in Corrective Colony No. 14 in the Mordovia region, southeast of Moscow. She said inmates at the colony were forced to work up to 17 hours a day sewing police uniforms.

She said workers received no more than four hours sleep a night and prison officials used senior inmates to enforce order in a system reminiscent of Soviet-era Gulag forced labour camps.

Collective punishment, increasing production quotas and cases of violence against those who failed to deliver were common in the penal colony, where living conditions failed to meet human rights standards and Russian law, she said.

"Your hands are pierced with needles and covered in scratches, your blood is all over the work table, but still you keep sewing," she wrote.

The Mordovia region's prison authorities accused Verzilov and Tolokonnikova's lawyer, Irina Khrunova, of blackmail and of trying to put pressure on the penal colony to give the musician special treatment.

"The output quota is the same for all convicts working in the sewing unit. No extra requirements were put on Tolokonnikova specifically," it said in a statement, adding that an inmate's working day is eight hours, including a lunch break.

Tolokonnikova said she had asked the regional arm of the federal Investigative Committee to investigate a senior prison official whom she quoted as saying after a complaint about conditions: "You will surely never feel bad again because it is never bad in the other world."

The committee's regional unit said it was looking into the accusations.

Kremlin critics say the sentencing of Tolokonnikova and two other band members is part of a crackdown on dissent since Putin returned to presidency for a third term in May 2012.

The Pussy Riot protest offended many in the mostly Russian Orthodox country but their treatment has also won them high-profile support in the West, including from celebrities such as Madonna and ex-Beatle Paul McCartney.

Tolokonnikova is due for release in March, as is fellow band member Maria Alyokhina. A third band member had her sentence suspended.

Alyokhina went on hunger strike in the summer after officials prevented her from attending a parole hearing. She was hospitalized in late May and ended her protest days after prison authorities agreed to her demands, Verzilov said.