Prison guards may have broken the Weapons Control Act when a group of youths were tear gassed at Darwin's Don Dale Youth Detention Centre, a lawyer for the four teenagers has told a Northern Territory court.

The group whose identities have been suppressed by the NT Supreme Court, are suing the Northern Territory Government over the incident.

The four teenagers are seeking damages from the NT Government, claiming the use of tear gas amounted to assault and battery.

In a pre-trial mention, the teenagers' lawyer Kathleen Foley told the court that while there were provisions to use tear gas in legislation for adult prisons, there was no such provision in the legislation for youth detention centres.

Ms Foley also told the court that submissions made by the NT Government in the case seemed to incriminate prison officers.

"Some of their evidence actually discloses an offence, a serious offence," she said.

Ms Foley said that without legal authorisation to use tear gas, it was possible the guards broke the Weapons Control Act, which could see them receive a maximum sentence of two years in prison.

She added that the NT Government did not appear to have claimed in their submissions that they did have legal authority for the use of tear gas in Don Dale.

"It's now clear that the NT does not say there's a question of authority," she said.

Justice Judith Kelly agreed, and said there appeared to be "no issue" as to whether there was legal authority to use tear gas.

'Mistake' in NT Government's submissions

Justice Kelly asked the lawyer for the NT Government, Trevor Moses, whether there was "a mistake" in the Government's submissions.

"Yes and no, Your Honour," he replied.

Mr Moses indicated he may amend the NT Government's plea on the issue.

"I have fumbled enough on that question right now," Mr Moses said.

Ms Foley told the court she was yet to receive any documents on rules for guards on what force was allowed in the discipline of Don Dale prisoners.

Mr Moses said there was "no single document" that could be provided.

"It's possible there could be tens of thousands of emails relating to discipline between the Superintendent [of Don Dale] and the Commissioner [for Corrections]," he said.

"It's a very murky area," Mr Moses said.

The trial is set to begin on Monday, September 26.