KazMunaiGas Exploration Production said on Monday it may cut its crude oil production forecast for the year after first-quarter output fell below target due to adverse weather conditions at oilfields in western Kazakhstan.

KazMunaiGas EP, the London-listed arm of Kazakh state oil and gas company KazMunaiGas, said in a statement that meeting full-year production targets at two major subsidiary companies "may be more challenging than previously anticipated".

The company said it produced 3.03 million tons, or 249,000 barrels per day, of crude oil in the first quarter of 2012. That was 5% less than in the same period last year.

Combined output at its major Uzenmunaigas and Embamunaigas subsidiaries fell 9 % year-on-year to 1.91 million tons, or 156,000 barrels per day, in the first three months of 2012. That was about 7 % short of its quarterly plan.

Combined production at the two fields has been forecast at 8.62 million tons for the entire year. The company said it still aimed to meet this target, but that second-quarter results would determine whether or not it would revise its forecast.

KazMunaiGas EP's net profit declined 11% last year due mainly to a strike at oilfields including Uzenmunaigas, which eventually erupted into Kazakhstan's worst violence in decades.

The company has set its full-year 2012 production target at 13.01 million tons, or 265,000 barrels per day.

KazMunaiGas EP said its share in first-quarter production from the Kazgermunai, CCEL and PetroKazakhstan joint ventures rose by 4% year-on-year to 1.12 million tons, or 93,000 barrels per day.

In a separate statement, the company said its proved plus probable reserves, excluding its joint venture stakes, totalled 225.82 million tons, or 1.66 billion barrels, as of Dec. 31.

Its reserves were assessed by independent auditor Gaffney, Cline & Associates. Its proved plus probable reserves replacement ratio in 2011 was 21%, the company said.