Queensland Gulf Indigenous leader Brad Foster has backed allegations of an attempted cover-up by the office of the state's Indigenous Policy Minister Liddy Clark.

Mr Foster has ended four days of silence on the issue to support Aboriginal Activist Murrandoo Yanner, who first raised the allegations.

The Crime and Misconduct Commission (CMC) is investigating claims Ms Clark's office tried to get Murrandoo Yanner and Brad Foster to lie about who was paying for airfares to Palm Island last week.

Mr Foster says he had no intentions of talking about it, but was forced to after hearing constant insults and lies from the Government.

He says he will also be telling CMC investigators about a disturbing phone call he received from one of Ms Clark's senior advisers urging him to lie about the airfares.

"I am not going to be involved in any cover-up, we are not lying about this?there is no reason for myself or Murrandoo Yanner to lie about the ticket issue," he said.

Mr Foster says the allegations are true and he strongly believes he was asked by Ms Clark's office to participate in a cover-up.

"I think it is important that Liddy Clark needs to show a little bit of leadership and actually stand up," he said.

"It seems as though the Premier and the Police Union applied a lot of pressure to Liddy Clark to change her decision about what happened."

CJC Chairman Brendan Butler says the allegations if proven could amount to official misconduct.

Ms Clark has gone on holidays and has strongly denied claims her office is involved in a government cover-up.