Eight drug prisoners, including two Australians, have been executed by firing squad in Indonesia, according to local media.

The convicted Australian drug smugglers Andrew Chan, 31, and Myuran Sukumaran, 33, were put to death early on Wednesday local time.

Four Nigerians, an Indonesian and a Brazilian national were also executed, reports say.

Indonesian authorities are yet to officially confirm that the executions have been carried out.

Chan's brother Michael said on Twitter: "I have just lost a Courageous brother to a flawed Indonesian legal system. I miss you already RIP my Little Brother."

A Filipina prisoner, Mary Jane Fiesta Veloso, was granted a last-minute reprieve.

The spokesman for attorney general's office said the death penalty for Veloso, who was arrested in 2010 after she arrived in Indonesia with 2.6kg of heroin hidden in her suitcase, has been delayed.

He said the delay came in response to a request from Manila after a drug courier gave herself up to police in the Philippines on Tuesday.

The death penalties were carried out by authorities at Besi prison on the island of Nusakambangan.

Twelve marksmen were assigned to fire at the heart of each prisoner, but only three would have live ammunition.

Authorities say this is so that the executioner remains unidentified.

Indonesia has harsh punishments for drug crimes and resumed executions in 2013 after a five-year gap.

In the lead up to the executions, Indonesia was criticised by the United Nations and Australia for its decision to execute the prisoners.

Earlier today family members paid their final visit to the prisoners and wailed in grief as empty white coffins arrived at Besi prison.

Crosses to be used for the coffins, inscribed with the date 29.04.2015, were made ahead of the executions.

Relatives of Sukumaran and Chan, the ringleaders of the so-called "Bali Nine" heroin trafficking group, cried as they headed to the island, with one relative collapsing.

"I am asking the government not to kill him. Call off the execution. Please don't take my son," said Sukumaran's mother Raji.

Chan and Sukumaran were arrested at the main airport on the holiday island of Bali in 2005 for trying to smuggle 8kg of heroin to Australia.

Chan married his Indonesian girlfriend at the jail in Nusakambangan prison island with family and friends on Monday - his final wish.