* Fighting inflation is Beijing's top priority this year
* Rate rise comes ahead of March inflation data next week
* Analysts say move could suggest March inflation strong
* One-year deposit rate 3.25 percent, lending 6.31 percent
* Rates increased 25 basis points, effective Wednesday (Adds more quotes, details)
By Soo Ai Peng and Tony Zhou
SHANGHAI/BEIJING, April 5 (Reuters) - China's central bank increased interest rates on Tuesday for the fourth time since October, raising suspicions that data next week may show inflation rose more than expected in March.
China's rate rise adds to six official increases in bank reserves since October and underlines Beijing's determination to clamp down on inflation, which leaders have declared as their most important task this year to keep the world's fastest growing major economy on track.
The increase comes before the European Central Bank is expected to raise its rates on Thursday for the first time since the global financial crisis, showing how inflation is rising to the top of the global policy agenda.
"The March inflation figures must be very high," said Xu Biao, economist with China Merchants Bank in Shenzhen.
"It is an aggressive move, and the central bank is acting more aggressively than the market had expected. The latest interest rate rise, although at only one quarter point, may hurt investor confidence and the real economy quite significantly. More importantly, it is not the end of China's monetary policy tightening."
Benchmark one-year deposit and lending rates were lifted by 25 basis points to 3.25 percent and 6.31 percent respectively, the People's Bank of China said in a statement on its website.
The rises take effect from April 6, when financial markets in China reopen following public holidays on Monday and Tuesday.
China is due to report the March consumer price index on April 15. Economists expect the data to show that consumer inflation rose to 5.1 percent in March, matching a 28-month high seen in November.
Inflation was 4.9 percent in February, unchanged from January. Beijing is aiming for inflation to average 4 percent this year.
Metals and crude prices eased after the news of China's rate rise on fears tighter policy will restrict the country's demand for commodities. The Australian dollar, a proxy currency for commodities, also fell. [ID:nLDE7340FY]
"We did expect a rate hike in April so it's not a complete surprise," said Allan von Mehren, chief analyst at Danske Bank in Copenhagen.
"They are raising rates to stem the inflationary pressures in the economy. We expect another two hikes of 25 basis points each this year. We are already seeing a slowdown in the Chinese economy but they need to raise rates a couple more times.
"They will still use reserve requirement increases but they also need to raise rates. I think they will use different tools (to tackle inflation)."
INFLATION PRESSURES
Food prices have been the main driver of China's inflation. Although monetary policy has little affect on food prices, since people have to eat, the tightening reflects concerns that price pressures will spread to other parts of the economy and so raise inflation expectations.
Underscoring those worries, consumer goods giants Procter &
Gamble and Unilever
Unilever agreed to comply with a request from authorities to postpone its price rises, the Financial Times reported on Saturday. [ID:nL3E7F200V]
Sharply rising commodities prices, including international crude prices that are hovering around their highest levels in more than two years, are another inflation threat.
The economy, which grew more than 10 percent in 2010, is vacuuming up commodities globally to satisfy the drive for growth.
Analysts have said they expect inflation in China to peak around the middle of the year.
"This rate hike suggests that the March CPI that is to be released early next week may have surprised to the upside. Our current CPI forecast is 5.2 percent y/y for March," said Qing Wang, an economist with Morgan Stanley in Hong Kong, in a note to clients.
"It also suggests that Chinese authorities are confident in the sustainability of underlying growth momentum."
There are some signs that the raft of monetary tightening, which has been accompanied with prices controls, is starting to take effect. Indeed, the central bank drained 300 billion yuan ($46 billion) in cash from money markets in March through open market operations after injecting cash in January and February, to add to the tightening.
A central bank survey released in March showed more households were satisfied with current price levels and saw less chance of rising inflation. [ID:nTOE72F01E]
Purchasing managers' surveys last week also showed price pressures were easing. [ID:nL3E7F104Q]
GLOBAL CONCERN
Most central banks in emerging markets in Asia and Latin America have raised interest rates as the regions emerged strongly from the global financial crisis.
But major central banks in the developed world are now showing signs of starting to catch up.
The European Central Bank is expected to raise interest rates on Thursday by 25 basis points to 1.25 percent after inflation rose above its target. [ID:nSLAUEE7RO]
Comments from some Federal Reserve policymakers have raised market expectations that the U.S. central bank is moving towards a tighter policy.
So far, complaints among Chinese about rising prices have amounted to little more than grumbles, but serious inflation has sparked social unrest in China in the past.
"This is ultimately good news because it reduces the risk of policy error in China that markets were getting nervous about," Benoit Anne, head of emerging markets strategy at Societe General, said of the rate rise.
"It reduces the danger of Chinese policymakers being too dovish and shows them addressing the mounting inflation risk which is a massive tail risk for emerging markets. We will see a few more hikes as China needs more monetary tightening."
The central bank boosted bank reserves, or the amount of cash that banks have to put aside, by 50 basis points to 20 percent on March 18.
The move locks up cash that banks could otherwise lend out and potentially fuel inflation. Excess cash stemming from China's vast trade surplus has been a root cause of the country's inflation. (Additional reporting by Kevin Yao, Zhou Xin and; Writing by Koh Gui Qing and Neil Fullick; Editing by Dean Yates)