Australia's largest Indigenous legal organisation says they received a record number of calls to their custody service in December as the Territory grapples with a horror rise in prisoner numbers.

Coming a day after chaos ensued at Darwin Court House on the first day a number of punitive laws - including the lowering of the age of criminal responsibility to 10 - came into effect, the North Australian Aboriginal Justice Agency (NAAJA) said the number of calls to its custody notification service (CNS) in December was the highest on record.

"The custody notification service is an early indicator of future pressures on the justice system in the Northern Territory and the news is not good," a NAAJA spokesperson said.

Established to reduce Indigenous deaths in custody and in response to recommendations from the 1991 Royal Commission into Aboriginal Deaths in Custody, there were 1,276 notifications of Aboriginal people being taken into custody in December.

This includes 144 notifications of young people—the second highest number on record.

"This represents an average of 41.2 Aboriginal people being taken into custody every day," the spokesperson said.

Monthly custody notifications in August 2019 were 571, NAAJA said, meaning an extra 701 Aboriginal people had been taken into custody in December last year.

Wadeye, one of Australia's largest remote Indigenous communities located approximately 420 kms south west of Darwin, saw a reported a 277 per cent increase in CNS from November to December.

On Monday, Corrections Minister, Gerard Maley, announced the number of prisoners in the NT had risen to a record 2,628—more than one per cent of the Territory's population.

Almost half are unsentenced.

The government has refused to apologise for the numbers, which now see the NT with the second highest incarceration rate in the world behind only El Salvador, arguing it is the price of "keeping Territorians safe".

The arrests since a change in the presumption of bail, known as Declan's Law, came into effect, appear to have already outpaced Darwin's holding cell facilities, with NT Legal aid lawyers saying on Tuesday only three of the 31 prisoners were in court cells and lawyers were unable to seek instructions from clients.

Corrections have grappled with the extraordinary numbers, set to increase as the new laws come into effect, with a number of restorative programs suffering.

AAP reported a man was remanded to custody on Monday despite being approved for community-based sentencing because the judge was told no family violence programs were running.

"We have had to cease some programs of rehabilitation in prison because of the demand of prison services is so high … the only other alternative is to leave criminals out on the street," Chief Minister Lia Finocchiaro said.

A 2023 Bail and Weapons Offences Review Taskforce report found 91 per cent of people granted bail whilst charged with a serious violence offence did not go on to reoffend in the community.

Some watch houses are being turned into prisons, with NAAJA saying they were unable to speak to, and check in on, 131 (33 per cent) of the people detained in the Palmerston watch house—one of the facilities to be converted.

In October, the government announced an increase in prison capacity across the NT to 3000 beds by 2028, with data currently showing only 2177 beds across the prisons and work camps network.

On Tuesday, Northern Territory Police Association's (NTPA) president, Nathan Finn, said it was only a matter of time before someone died in custody.

"There's going to be a high risk of people actually dying within our cells," he said.

NAAJA highlighted Mr Finn's comments, with a spokesperson arguing: "'Northern Territory jails and watch houses are already full and more and more Aboriginal people are being pushed into the justice system at record numbers every month."

"This is going to have a devastating impact on Aboriginal communities and families for generations to come and it is not reducing crime. Jail is not the only solution."

NAAJA reiterated their previous calls for increased funding and policy changes to address the underlying causes of crime, as well as offering greater support for the justice system and better safeguards for Aboriginal people's wellbeing in custody.