British-born human rights activist Joan Jara, the widow of Chilean folksinger Victor Jara murdered by dictatorship agents in 1973, has died aged 96, the foundation she created announced.

"Our beloved Joan Jara passed away" on Sunday, the Victor Jara Foundation said on social media. A memorial service will be held in Santiago Monday.

Born Joan Turner, Jara went into exile with her two daughters after her husband's murder in 1973, returning to Chile in the mid-1980s to fight for truth, justice and human rights.

Also a decorated dancer, she denounced the dictatorship and its violations, seeking justice for her husband's death. She received Chilean citizenship in 2009.

Victor Jara, 40, was arrested the day after the September 11, 1973 CIA-backed coup that overthrew Salvador Allende and installed Pinochet as dictator.

Jara's body was found days later, riddled with 44 bullets. He had been held, along with around 5,000 other political prisoners, in a sports stadium where he was interrogated, tortured and then killed.

In 2016, Joan Jara told the US-based civil trial of Pedro Pablo Barrientos Nunez, charged with torturing and killing her husband, how his death "changed my life, and the life of my daughters, forever."

She recalled finding Jara's lifeless, mangled and bloodied body in a morgue.

Barrientos, who the court found liable for the murder, was arrested in Florida last month and is expected to be extradited to Chile where he has been wanted since 2013.

Weeks before his arrest, Chile's Supreme Court sentenced seven retired military officers to up to 25 years in prison for Jara's kidnapping and murder.

One of Chile's most beloved folk singers, Jara became an icon for those who suffered human rights violations under Pinochet, and inspired artists internationally including U2, Bob Dylan and Bruce Springsteen.