Australia is pursuing a last-ditch deal with Indonesia to save two of its citizens from imminent execution on drugs charges, Foreign Minister Julie Bishop said on Thursday, in a case that threatens to strain already fragile relations.

Myuran Sukumaran, 33, and Andrew Chan, 31, are among eight prisoners due to be executed after Indonesian President Joko Widodo rejected their clemency pleas last month.

Five foreigners were among six people executed for drug offenses last month, the first executions in Indonesia since Widodo took office in October. Indonesia has since rejected Australian pleas for clemency for Chan and Sukumaran.