Chilean forensic experts have exhumed the body of Nobel laureate Pablo Neruda to solve a four-decade mystery about the poet's death, hoping to determine if he died of cancer or was poisoned.

Patricio Bustos, head of Chile's medical legal service, said Neruda's body was in good shape after the one-hour exhumation on Monday.

"The time and the conditions under which the exhumation were performed were better than we could have imagined," said Bustos.

Tomb opening preparations began Sunday. His remains are in a tomb at one of his homes in Isla Negra that was turned into a museum.

Neruda, who died 12 days after the 1973 military coup that ousted Chile’s socialist president Salvador Allende and brought General Augusto Pinochet to power, was long believed to have died of prostate cancer.

But in 2011, officials started looking into the possibility of whether the leftist author was poisoned by agents of the Pinochet regime, as claimed by Neruda's driver.

Neruda won the 1971 Nobel Prize in Literature and is best known for his love poems, as well as his "Canto General", an epic poem about South America's history and its people.

The Chilean justice system gave the go-ahead for the probe in June 2011 after a complaint was filed by the Chilean Communist Party, of which Neruda was a member.

In addition to the driver's accusations, the official complaint cites witnesses who say Neruda was healthy up until the day before his death. They said he did not exhibit symptoms consistent with the advanced cancer to which he was said to have lost his life.

The results of the inquiry will find in favour of, or against, the charge made by Neruda's driver and personal adviser Manuel Araya, who believed the poet was slain. Araya's claims spurred on the Communist Party's complaint.

Araya says Neruda died after receiving what the driver believed was a suspicious injection at Santiago's Santa Maria Hospital days after the coup that brought Pinochet to power.

In the years following the military coup, more than 3,000 leftists and others “disappeared” and are believed to have been killed by Pinochet’s government.

Neruda's death certificate says he died of complications from prostate cancer.