A PAIR of Australians on death row in Indonesia may have only days left to say goodbye, after the bureaucratic wheels for their execution started turning again this week.

The Bali Nine ringleaders Andrew Chan and Myuran Sukumaran have attempted several legal challenges to their death sentences. All have been rejected by Indonesian courts.

But the ABC has reported that his week an Indonesian official sent letters ordering that "preparations" start for their execution on Nusa Kambangan Island.

While the letter did not constitute the final "72 hours' notice" usually sent, it followed local media reports this week it was "only a matter of time".

Indonesian President Joko Widodo has repeatedly rejected international appeals for clemency for them.