A top legal expert says Tom Phillips' children should not be forced to identify their father's accomplices after spending four years on the run with him in New Zealand's King Country bush.

Phillips vanished from the rural town of Marokopa in December 2021 with his children following a custody dispute with their mother.

But despite police offering a $80,000 reward, no one turned them in.

Investigators believe he received help during this time and are now turning their attention to identifying those who may have supported him.

'Aside from the burglaries we are now able to link to Tom, it is apparent that he had outside help,' Det Saunders said.