Sukumaran draws on his faith, pastor says

One of the Bali nine ringleaders facing execution will probably spend his final moments praying and singing worship songs, a Melbourne pastor who has befriended him says.

Myuran Sukumaran has chosen to spend his final hours with Melbourne pastor Christie Buckingham, who will also witness his execution.

Her husband Pastor Rob Buckingham said he has spoken to his wife and expected Sukumaran would draw on his Christian faith in his final hours.

"They will talk, they will probably pray and maybe sing some worship songs together," Mr Buckingham told 3AW radio.

"Myuran has drawn very close on his faith over the last few months."

Indonesia hasn't said exactly when Andrew Chan and Sukumaran will face the firing squad but it's understood the men's families have been told to say their last goodbyes by 2pm on Tuesday (5pm AEST) before the executions are carried out on Nusakambangan island, Central Java, after midnight.