Sinai told The National newspaper that the Australian Defence Force aircraft would transport the printed ballot papers to PNG in May.
"There will be about 12 million ballot papers printed - six million for the open electorates and six million for the provincial or governors' seats."
Sinai said that the indelible ink would be used during polling to mark the fingers of those who had cast their votes.
He said the Electoral Commission was preparing for the issue of writs in April and was updating donor agencies, diplomatic corps, New Zealand, Australia and the United States on PNG's election preparedness.