Output by OPEC oil producers has reached record levels, the International Energy Agency said Thursday, raising fears a global oil glut will continue to weigh on markets unless the cartel agrees on a cut.

Production by the 14 members of OPEC rose to "a record 33.83 million barrels per day in October", the IEA said, just weeks ahead of talks aimed at hammering out a deal to curb production.

In a surprise move, OPEC (the Organization of the Petroleum Exporting Countries) members, led by oil kingpin Saudi Arabia, agreed in Algiers in September on a deal to trim production, sending crude prices surging.

The accord aims to stabilise prices that have dramatically fallen since 2014, deeply hurting producers across the board, but its details are to be determined at OPEC's meeting on November 30 in Vienna.

The Paris-based IEA, which advises oil consuming nations on energy issues, said OPEC had hiked its output for five months running, led by Iraq and Saudi Arabia.

Its October level was "well in excess of the high end of the proposed output range", the agency said in its monthly report on the oil market. 

"This means that OPEC must agree to significant cuts in Vienna to turn its Algiers commitment into reality," it added.