The Commonwealth and NT Government have agreed to extend the Royal Commission into the Protection and Detention of Children in the Northern Territory by four months.
The extension will be accommodated within the existing budget.
The new reporting date will be August 1 next year, and the commission will release an interim report on March 31.
"Given the importance of the royal commission's work, both [the Northern Territory and federal] governments consider that it is reasonable and appropriate to grant the short extension," a joint statement from NT Chief Minister Michael Gunner and Federal Attorney-General George Brandis said.
"No further extensions will be granted."
In September one of the commissioners in charge of the royal commission, Mick Gooda, said it was not possible to meet the existing reporting deadline and an extension was needed.
Mr Gooda said the extension was needed to fulfil the tasks set out in their terms of reference and that he and co-commissioner Margaret White had endured "sleepless nights about meeting the deadlines".
The royal commission has been asked to make recommendations about legal, cultural, administrative and management reforms to prevent inappropriate treatment of children and young people in detention, and to decide what improvements can be made to the NT's child protection system.