Police have laid out some of the challenges they faced in their hunt for Marokopa fugitive Tom Phillips

They've revealed they knew Phillips was unlikely to surrender, had firearms and was motivated to use them, and was prepared to put his children in harm's way.

Police say they dedicated thousands of hours to the search and enlisted specialist units and the Defence Force.

They say the family was detected in transit on occasion but never when officers could safely intervene.

Newstalk ZB's Jordan Dunn says they also described the harsh environment they were searching in.

He says it was steep terrain which was almost entirely obscured by deep bush.