"If they (the other members) don't vote for Iran's candidate ... there is no reason Iran should vote for others," Oil Minister Bijan Namder Zangeneh said on Saturday.

Venezuela's Alvaro Silva Calderon is seeking a new mandate as chief of the Organisation of Petroleum Exporting Countries, but both Iran and Kuwait have also put up candidates for the strategically important post.
 
The Iranian minister said Tehran's position had not changed.

"There are three nominations, Iran, Venezuela and Kuwait. The ministers have to decide. And if they couldn't decide, based on OPEC's charter, the election should be done based on alphabetic order," he said, reiterating a suggestion that OPEC could resort to a rotating leadership.

At a meeting in Vienna in September, OPEC ministers were unable to reach any agreement on who should lead the cartel, an appointment that has to be made by consensus. The cartel is due to meet on 4 December.