Family members of a Filipino maid facing the death penalty after being convicted of drug trafficking in Indonesia have made a last-minute appeal for clemency to the country's president.

The parents, siblings and two young sons of Mary Jane Veloso delivered the open letter to President Joko Widodo to the Indonesian Embassy on Wednesday and appealed for "mercy and compassion" for the 30-year-old single mother.

The letter says Veloso was tricked by a compatriot into carrying 2.6 kilograms (5.7 pounds) of heroin in her luggage, and says she was a victim of drug syndicates.

Indonesia's highest court last month rejected a judicial review petition by Veloso, who is among 10 foreigner drug smugglers facing death by a firing squad.