Indonesia rejected on Thursday an Australian proposal for a prisoner swap made in an eleventh hour effort to save the lives of two Australian drug smugglers expected to face a firing squad within days.

The planned executions of Myuran Sukumaran, 33, and Andrew Chan, 31, have increased diplomatic tension between Australia and Indonesia after repeated pleas for mercy on their behalf. They are among a group of up to 11 convicts, mostly foreigners, due to be executed on the prison island of Nusakambangan.

Indonesia's Foreign Ministry said there was no legal basis for Indonesia to act on the proposal that had been made by Australian Foreign Minister Julie Bishop.