* Joint Organisations Data Initiative data differs from Moscow
* JODI -Russia March output 9.920 mln bpd vs Saudi 9.923 mln
* Russian data - Russia output about 10.33 mln bpd early 2012
MOSCOW/DUBAI, May 21 (Reuters) - Russia has been pumping hundreds of thousands of barrels of oil a day more than Saudi Arabia and is confident it can increase output year on year, Energy Ministry data showed, contradicting a report the kingdom has become the world's biggest producer.
Data from a Russian energy ministry presentation obtained by Reuters follow a report published over the weekend by the Joint Organisations Data Initiative (JODI) - a group set up by oil producers and consumers - showing a sharp drop in Russian output.
JODI data showed Russian production fell from 10.370 million barrels per day (bpd) in December to 9.920 million in March, marginally less than Saudi Arabia's 9.923 million bpd that month.
But the energy ministry's data showed daily average output was steady at about 1.41 million tonnes, or about 10.33 million bpd in early 2012, up from 10.31 million bpd in December.
The ministry's outlook for 2012, based on those production figures, says the country is on track to meet its target of averaging 10.31 million bpd for the year, higher than any month of last year.
"It looks like an issue with JODI methodology," a Russian source said.
JODI was set by oil producer bodies including the Organization of the Petroleum Exporting Countries (OPEC) and consumers such as the International Energy Agency (IEA) to improve the transparency of oil market data. It relies on timely submissions of data from individual government agencies.
JODI officials did not respond to emails on Monday to comment on why the data differed so much from Russian figures.
JODI's data disclosure by individual countries says it includes output of condensate - light hydrocarbon liquids - from Saudi Arabia in crude production figures.
It does not say if it includes Russian condensate and adds that for Russia it "had changed the definition of crude oil stocks to exclude the so called "reserves" which was not explained further by Russia".
"At the same time, Russia also stopped reporting stock level data of total oil," JODI said without elaborating.
Russian officials were not available to comment on changes made by JODI.
Saudi Arabia says it has the capacity to pump about 12.5 million bpd if oil markets are hit by supply shortages, but it has never tested those levels.
Russia has little to no spare capacity and its government has been trying to re-engineer the tax regime to coax additional barrels out of its old fields in Western Siberia.
Western Siberia, which accounts for more than 60 percent of total Russian output, is in decline, though the rate has slowed to less than 1 percent last year, according to analyst calculations.
The rampup of new East Siberian fields such as Rosneft's Vankor and TNK-BP are offsetting those declines.
Russia has reported no major outages at its fields or pipeline infrastructure this year and refinery runs were up year on year.