Six people, including five foreign nationals, have been executed by firing squad in Indonesia after they were convicted on drug charges.

The foreigners, from Brazil, the Netherlands, Vietnam, Malawi and Nigeria, were executed shortly after midnight, authorities said, despite international appeals.

The sixth, an Indonesian women identified as Rani Andriani, was also killed.

"The execution of the six convicts has been carried out," spokesman for the attorney general's office, Tony Spontana, told news agency AFP.

Brazilian President Dilma Rousseff had issued a last-minute plea to Indonesian authorities to spare former pilot Marco Moreira.

It was rejected by Indonesian President Joko Widodo who said the judicial proceedings had followed Indonesian law.

The Dutch government had issued a similar appeal for its citizen Ang Kiem Soei.

Clemency appeals for the pair, as well as Namaona Denis of Malawi, Daniel Enemuo of Nigeria, and female convict Tran Thi Bich Hanh of Vietnam were rejected in December.

All six had been sentenced on drug charges from 2000 to 2011.

"What we do is merely aimed at protecting our nation from the danger of drugs," Attorney General Muhammad Prasetyo told reporters on Thursday.

"There is no excuse for drug dealers, and hopefully this will have a deterrent effect."

Five of the convicts were killed on Nusakambangan Island, off the south coast of the Indonesian island of Java.

The sixth was killed in Java's Boyolali district.

They were the first executions carried out since President Widodo took office in October.

At least 138 people are on death row in Indonesia, mostly for drug offences.

Roughly a third of them are foreigners.