At present there is no Iraqi authority or government, so Iraq cannot be treated as a member, the acting chief Thamer Ghadhban told a press conference in Baghdad.
"We are not attending the meeting and we are not invited to anything" to do with the Organisation of Petroleum Exporting Countries (OPEC), he said.
The organisation's next meeting is expected to be held in Vienna on July 31.
Whether Iraq stays in the organisation or not would be a decision to be taken by a future Iraqi government, he said, adding that "we hope we will have a national government very soon."
US-led occupation forces running Iraq say it does not expect a permanent Iraqi government to be formed for at least a year.
“Any decision to attend the meetings will be taken by the future government and I look forward to having a normal relationship with OPEC," he said.
Ghadhban said last week he would prefer Iraq to stay inside OPEC. "Why should we pull out, it's premature," he said. "I don't think we are going to pull out. We don't have any problem with OPEC."
OPEC's role will be significantly diminished if Iraq ultimately chooses to withdraw, as it would deprive the organisation of control over 112 billion barrels of proven reserves, the second largest in the world behind Saudi Arabia.