The Organization of the Petroleum Exporting Countries hasn't been effective in stabilizing oil prices, which have been more dependent on U.S. shale production than the actions of the intergovernmental group, said Malaysian Prime Minister Mahathir Mohamad.

"OPEC is not effective. They are always at loggerheads with each other so they cannot make decision," Mahathir told CNBC's Sri Jegarajah in a Monday interview. The Malaysian leader was asked whether the group should take further action to stabilize oil prices.

"What is more important is the production of shale oil from America," he added.

Those comments by the Malaysian leader came less than a month before OPEC and non-OPEC members are scheduled to meet in Vienna, Austria to vote on their next policy decision. Those major oil producers began cutting production in January 2017 to drain a global crude glut that sent oil prices from over $100 per barrel to under $30.

Oil prices did recover, but trade tensions between the U.S. and China, rising interest rates and currency weakness in emerging markets have raised concerns about a slowdown in global economic growth and oil demand.