Mehrtens was providing vital air links and supplies to remote communities at the time of his abduction by rebels from the West Papua National Liberation Army (TPNPB) insurgent group.
His release came after intense diplomatic efforts by Wellington and Jakarta.
The Indonesian task force would hold a press conference later on Saturday, Faizal said.
Rebels had demanded Indonesia recognise Papuan independence in return for his freedom.
A New Zealand Ministry of Foreign Affairs and Trade spokesperson said it would comment later.
The TPNPB did not respond to a request for comment.
VIDEO ADDRESSES
Last year, the independence fighters of the TPNPB set fire to the Susi Air plane, released five other passengers but held on to Mehrtens.
During his months-long ordeal in the Papuan countryside, the New Zealander made sporadic appearances on video, likely under duress, to address his family and his government.
The rebels said he was in good health throughout his captivity, but his appearance changed drastically over time, becoming gaunt, long-haired and with an unkempt beard in proof-of-life videos where he asked for medication to aid his asthma.
