Russia, Saudi Arabia, Iraq, and other OPEC members who agreed last year to curb production to bolster oil prices now want to prolong the agreement, in a strong sign that an extension will be formally approved at a meeting on May 25.
The 13-country Organization of the Petroleum Exporting Countries agreed to cut production by 1.2 million barrels a day in November, while Russia, Kazakhstan, and other non-OPEC producers cut production by 600,000 barrels a day.
That deal, which has helped push up oil prices, is due to expire on June 30.
OPEC Secretary General Mohammad Barkindo said there is "growing consensus" for a nine-month extension while Iranian oil minister Bijan Namdar Zanganeh told reporters there was already apparently unanimous agreement to continue November's cut.
Saudi Arabia, Russia and Iraq came out in support of an extension earlier.
At around $50 a barrel, benchmark premium crude prices are up from lows below $30 reached in early 2016. But prices are still around half the levels reached in 2014.
The higher prices have enticed U.S. shale oil producers to increase output by nearly a million barrels a day, offsetting some of OPEC's cuts.