But yesterday he said he was still waiting for Nigerian inmate Silvester Obiekwe, and "more than three" others, to be notified their clemency applications had been rejected before proceeding.
President Joko Widodo had signed the correspondence but it passes through several hands before arriving with the prisoners concerned.
Indonesia already has eight drug offenders in line for execution - one Indonesian, the two Australians and five other foreigners.
It means as many as 12 prisoners could be executed in the next round.
"I hope it will be issued immediately," Mr Prasetyo said of Obiekwe's letter.
"This time it will take more time because those to be executed are not in one place, they are scattered in several prisons."
Embassies and families have to be notified and police, religious leaders and doctors readied, Mr Prasetyo said.
"As I've said, this is not a fun job, not a pleasing job, but we have to do it."
Authorities want Obiekwe to face the firing squad soon, after he was caught running a drug racket from behind bars on central Java's Nusakambangan island, also the likely location for the executions.
- AAP