"We evaluated the previous execution and we made improvement last night that everything was carried out humanely," Prasetyo said here on Wednesday morning.
Prasetyo made the statement after visiting the locations of execution of 8 death row convicts mostly drug convicts.
He said the process was not a pleasant duty but it was done for the safety of the nation from drug crime.
"We are not against the nations, the home countries of the convicts executed last night. We are fighting against drug crimes. We were sad in doing the duty , shared the sorrows and we offer condolences to the relatives of the executed convicts and to their respective countries," he said.
He said Indonesia will continue to take firm measure against drug crimes.
He said many have criticized that the government was too slow in carrying out the execution.
"We want to be precise. We are ony being careful that no law is broken . Everything has to be in line with regulation and law," he said.
He said he had thought over the suggestion of moratorium in death sentenced , but he expressed doubt that it could help Indonesians facing death penalty in other countries.
"What is certain is that whatever we have done related to the execution of the death row convicts , we did it in line with the regulation. No loophole is left.
"That is why we looked slow in in carrying out our duty and consequently criticized ," he said.
He said originally there were nine to be executed , but in the last minutes , the Philippines government asked for the postponement of the execution of one of the convicts Mary Jane.
Mary Jane was needed to give testimony in human traffic case.
"We respect due process of law in the Philippines . Therefore, execution of Mary Jane is postponed not cancelled," he said.
The eight executed 35 minutes past midnight on Tuesday were Andrew Chan and Myuran Sukumaran of Australia, Raheem Agbaje Salami of Nigeria), Zainal Abidin of Indonesia), Rodrigo Gularte of Brazil, Silvester Obiekwe Nwaolise alias Mustofa of Nigeria), Martin Anderson alias Belo (Ghana), and Okwudili Oyatanze of Nigeria.
They were declared dead 30 minutes later.
The bodies of Andrew Chan, Myuran Sukumaran, Rodrigo Gularte, and Silvester Obiekwe Nwaolise were sent to Jakarta before they were flown to their respective countries .
Three other were to be buried in the country including Raheem Agbaje Salami in Madiun, Martin Anderson in North Bekasi and Okwudili Oyatanze in Ambarawa as they requested .
The body of Zainal Abidin, the only Indonesian was buried in Cilacap .