The Don Dale Youth Detention Centre will be shut down within three months and sweeping changes made to address "shocking and systemic failures" in the Northern Territory's youth justice system after a landmark royal commission.

The final report of the royal commission into NT child detention and protection declared the system had long failed to rehabilitate children, protect human rights and comply with relevant laws, saying the problems "occurred over many years and were known and ignored at the highest levels".

Handed down 15 months after the royal commission was established to deal with shocking revelations out of the Don Dale facility, the report has also recommended the creation of a new children's court and that the age of criminal responsibility be lifted from 10 to 12, which would be a first in Australia.

The commissioners said no child under the age of 14 should be in detention unless convicted of a serious and violent crime and posing a genuine risk to the community. They found the use of force and isolation should be limited while tear gas and "spit hoods" – famously used on 17-year-old Dylan Voller – must be banned.