A gulf Aboriginal leader is questioning why the Queensland Police and the Criminal Misconduct Commission (CMC) have not told the public that there is a security video taken on the night Cameron Doomadgee died in custody on Palm Island.

Brad Foster says an investigator with the CMC has told him the tape was recorded in the Palm Island police station.

Mr Doomadgee, 36, died in the island's watch house on November 19, after he was arrested for creating a public nuisance.

Mr Foster says he also has independent witnesses, who saw the security cameras being switched on well after Mr Doomadgee was locked in his cell.

"One of the witnesses that was in the office had seen that the TV and video were turned off at the time," Mr Foster said.

"As they put him [Mr Doomadgee] into the cell and locked up the cell, they then walked back into the police station and then turned back on the video recorder and the TV."

Mr Foster says the witnesses are in hiding.

"Well because of the important information they have given me, and no doubt the CMC and the police have already done statements with those young fellas, and they could see that the information they have written down is very damaging.

"It is very important that I told them that they need to go away in hiding and that is something that I am worried about."

President of the Australian Council for Civil Liberties Terry O'Gorman says it is an important development in the Palm Island investigation.

"Clearly any allegation that the video recording in the watch house, which is standard equipment and which should operate 24 hours a day and which should never be turned off [is serious]," Mr O'Gorman said.

"Such an allegation has to be given prominence in the coronial hearing because it is a very serious allegation."

Mr O'Gorman says if the Palm Island station had a video surveillance system it should have been on all the time.

"The video recordings were introduced because there were an ongoing rash of complaints being made about citizens being assaulted in the watch house," Mr O'Gorman said.

"Every watch house in the state has continuous 24-hour recording if there is any truth in this allegation it is an extremely serious allegation."

A spokeswoman for the Police Minister Judy Spence says it would not be appropriate to discuss matters which are the subject of a CMC investigation and a coronial inquiry.