Key Points:

A 21-year-old man has today been charged with the murder of a 16-month-old Northland boy who died last week.

The arrested man will appear in Kaikohe District Court tomorrow charged with murdering Kerikeri toddler Riley Justin Osborne.

Riley died in Starship Hospital in Auckland on Tuesday of significant head injuries, four days after being flown from Northland.

Police had earlier described the injuries as "non accidental' and "horrific".

The arrested man, a beneficiary, will also face a number of drug-related charges.

Police thanked members of the public and of the boy's extended family who had helped the investigation team.