Indonesia's president has rejected any attempts by other countries to intervene in the execution of foreign drug traffickers.

The government has announced plans to execute eight people — one Indonesian and seven foreigners from Australia, Brazil, France, Ghana, Nigeria and the Philippines.

President Joko Widodo told reporters on Tuesday that the death penalty is part of the country's legal system, and insisted that other countries should not interfere.

He said he has received phone calls from some foreign leaders asking that the executions be canceled.

In January, the government brushed aside appeals from several foreign countries and executed an Indonesian and five foreigners from Malawi, Nigeria, the Netherlands and Vietnam who were convicted of drug trafficking.

There are 133 people on death row in Indonesia, including 57 for drug crimes.