More details emerge around the last known movements of 11-year-old Michael Zhao-Beckenridge and his step-father John Beckenridge

Coroner Marcus Elliot is taking a fresh look at one of New Zealand's most baffling missing persons cases.

The hearing's expected to take two weeks and has already heard evidence from witnesses including Police and staff at the boy's Invercargill school.

One staff member, who was one of the last people to speak to Mike Zhao-Beckenridge described him as "out of breath and panicky" that day.

Police have also revealed they found a plaster with his DNA near a concealed tent in the area, days later.