VIENNA, SEPT. 11 -- OPEC is planning a new oil output control system to discourage member countries from overproducing and to provide a more accurate tabulation of the cartel's overall production.

Organization of Petroleum Exporting Countries conference President Alhalji Rilwanu Lukman of Nigeria announced the plan at the conclusion of a two-day special meeting of two special oil ministers' committees dealing with the oil glut and falling spot market prices.

Lukman told a news conference the "compliance committee" that he will head with the oil ministers of Indonesia and Venezuela will visit all OPEC member states to urge adherence to the organization's national output quotas. The visits will start in October with Saudi Arabia and the other gulf states, which are believed to have massively exceeded production limits. The three-man delegation plans to visit Saudi Arabia, the United Arab Emirates, Qatar, Kuwait, Iraq and Iran and then the African states of Libya and Algeria.

The International Energy Agency reported OPEC's overall output has reached 19.7 million barrels daily -- far beyond the 16.8 million barrel quota set by the oil ministers' conference in June.

Lukman dismissed the agency's figures as "guestimates." He said OPEC's overproduction is between 1 million and 1.2 million barrels a day above the ceiling.

The over production is the result of increased consumer demand caused by fears of a possible disruption of supplies from the gulf, Lukman said. Now this demand is slackening and OPEC's output is dropping. OPEC production figures for the last week of August were lower than the average for the entire month, he said.

Lukman convened the panels last month after oil prices had fallen by about $4 a barrel.

Yesterday West Texas intermediate, the key U.S. crude for immediate delivery on the New York Mercantile Exchange, was down 33 cents to $19.34 a barrel at midday as traders showed disappointment over OPEC's new policing efforts. Prices slipped by as much as 25 cents a barrel on the European spot market.

Lukman announced OPEC would decide on an independent means of carrying out "physical production monitoring" in member nations. This system will be used for the tabulation of the official output figures and is to be finalized by the next oil ministers' summit to be held in Vienna in December.

Lukman said he expects oil prices to remain stable at present levels in the near future and that an increase of the OPEC benchmark crude price from the present $18 per barrel will be discussed at the December summit. He said contacts established with non-OPEC producing countries would be maintained to strengthen prices and to stablize the market.

Western oil experts who followed the OPEC meeting expressed doubts that the production control plan will work.