MOSCOW, April 22 (Reuters) - Russia’s statistics office will make monthly jobless reports secret, a newspaper reported on Wednesday days after data showed unemployment was soaring fast and experts said it was the biggest threat to social stability.

On Monday, Rosstat reported that some 1.8 million Russians lost their jobs in the first three months of 2009, taking the jobless rate to an 8 year-high. [ID:nLK123156]

But it was the first time it did not reveal monthly figures and Kommersant business daily quoted unnamed sources as saying reports would now be made public only on a quarterly basis. Rosstat declined to comment.

According to Reuters calculations, unemployment hit 11.9 percent in March from 8.5 percent in February, assuming previous data was unrevised. Some 500,000 Russians lost jobs in January, some 300,000 in February and the latest data suggested a record 700,000 became unemployed in March.

Officials had been saying that the worst of the crisis may be over for Russia, taking heart from higher global oil prices, a stabilisation of the rouble and a recovery in domestic stocks.

But international financial organisations, such as the World Bank, have said the economic slump could be much deeper than the government’s predictions and urged Russia to boost spending to stave off social unrest.

“The shift (in jobless data reporting) could imply a huge leap in March that Rosstat is seeking to smooth over with this new reporting method,” said Rory MacFarquhar from Goldman Sachs.

“A more sympathetic - and optimistic - explanation would be that the statistical authorities have simply decided to stop interpolating monthly figures from less frequent household employment surveys to avoid distortions that have arisen during the current turmoil on the labour market,” he added.

The government expects an economic contraction of just 2.2 percent in 2009, but international organisations and think tanks have said the slowdown could be at least twice as sharp.

Steering Russia through the financial crisis after years of oil-fuelled economic boom poses a key challenge for President Dmitry Medvedev and Prime Minister Vladimir Putin.

At 7.1 million [ID:nMOS005419], the number of unemployed is already over a million higher than the Economy Ministry forecasts for 2009 as a whole [ID:nLI604919] as companies slash jobs in the face of falling global and domestic demand and the inability to attract fresh financing.

Rosstat uses international methods to calculate jobless rates and its figures come in sharp contrast with official jobless rates of the state employment office, which says there are only 2 million jobless in Russia. [ID:nNLB933194] (Reporting by Yelena Fabrichnaya and Dmitry Zhdannikov; editing by Stephen Nisbet)