That was decided during a meeting of about 20 members of the group in Havre earlier this week.
The group, which has protested government actions at Rocky Boy - most recently a secretarial election held on the reservation in 2002 - met at the request of its spokesman, Russell Standing Rock, after he was arrested Tuesday for the second time in two weeks.
Standing Rock told the group the arrests were politically motivated because he had filed criminal complaints against the tribe in tribal court alleging financial abuses by the tribal council.
The tribe's attorney Wednesday said the tribal council had nothing to do with Standing Rock's arrest.
"We want to write a letter to the business committee (tribal council) to tell the business committee we want an overall audit," Standing Rock said at the meeting.
Arnold Four Souls, a former tribal council member, said at Tuesday's meeting that the council is not open with financial documents.
"You should be open to go up there and see how much money we have," Four Souls said. "It should be open, but it's not."
Group members complained that there is not enough financial oversight on the reservation, particularly over the use of earnings from the casino and a tribally owned farm. They also questioned tribal spending for the annual powwow.
Tribal attorney Dan Belcourt said Wednesday the tribe is closely regulated.
"We are the most regulated entity on the planet," he said.
He said an audit is regularly done on the tribal casino by an outside auditing firm and turned into the National Indian Gaming Commission.
He also said Standing Rock's arrest was not politically motivated.
"There's no political motivation at all," Belcourt said. The tribal council, he said, has "an agenda full of items that we're dealing with, and this is definitely not one of them."
Tribal council members did not return calls this week asking for comment.
People at the meeting also complained about abuses they said were committed by tribal police.
Grace Her Many Horses, the criminal investigator at the Rocky Boy Police Department, attended the meeting.
"I work at the police department and there's been a lot of complaints," she said after the meeting. "I'm just here to be informed about what's going on." Her Many Horses said she would take the complaints back to her supervisor, Myron Oats Sr.
Standing Rock said he will probably draft the letter requesting the audit by the time the group meets Wednesdsay at 6 p.m. at the TownHouse Inn in Havre.
If the group gets no response, he said, it will send a letter to the Bureau of Indian Affairs field officer at Rocky Boy, James Montes.
If Montes does not respond, they said they may try to pursue legal action against the tribe and the BIA in federal court.
Standing Rock was arrested earlier this week on charges stemming from an incident that occurred Feb. 25 in tribal court.
An argument broke out between Standing Rock and a man whose wife Standing Rock was representing in a divorce case, said tribal prosecutor Geneva Stump. The verbal argument escalated to a scuffle outside the tribal court building.
Standing Rock said the man swung at him and he kicked back.
Stump, who was outside on a cigarette break, said she immediately went inside. Another court employee called tribal police.
Tribal police responded and arrested both men on charges of disorderly conduct, she said. Standing Rock was also charged with threat and intimidation for comments he allegedly made to a court employee, and with assault for allegedly yelling and swearing at court staff and police.
On the way to the parking lot Standing Rock had to be restrained and was cited on a charge of resisting arrest, Stump said.
Standing Rock said he did not resist arrest, and that the police used excessive force for no reason, spraying him with Mace and injuring his arm.
Both men were taken to jail, Stump said. Standing Rock was bailed out by a family member.
Two days later Standing Rock was ordered to appear in court for arraignment on March 2.
On March 1 a restraining order requested by Stump was served against him.
When he did not show up for the arraignment on March 2, a warrant was put out for his arrest for contempt of court.
"I didn't show up because I was ordered not to be there," Standing Rock said.
Stump said the restraining order said he could show up at the court with adult supervision.
She also said the arrests were not politically motivated.