* Commodity FX tumbles after China ups bank reserve ratios
* Aussie hits day's low vs dollar, yen
* China announcement raises concerns about global recovery
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LONDON, Jan 12 (Reuters) - Commodity currencies slipped on Tuesday after China said it would tighten banks' reserve requirements, raising concerns that the tightening move may slow global economic recovery.
China's central bank said it was raising the reserve requirement ratio by 0.5 percentage points, effective Jan. 18, in the clearest sign yet that it has begun to tighten monetary policy.
Commodity-linked currencies including the Australian, New Zealand and Canadian dollars hit session lows against the U.S. dollar, following a sell-off in gold prices. They also tumbled against the yen.
The announcement underlined the risk tied to those currencies which, along with commodities, rallied for much of 2009 on the view that the global economy was on a recovery path.
China is a major importer of world commodities and a drop in its demand is seen as negative for commodity-linked currencies.
"It's an indication that the China authorities are being reasonably pro-active and it's going to put a bit of a two-way risk in the idea that commodity currencies are on such a solid path," said Paul Mackel, currency strategist at HSBC in London. "It's probably going to keep these currencies under pressure, at least in the short term."
The Australian dollar fell 1.1 percent to the day's low of $0.9205, pulling it away from a two-month high of $0.9326 hit on Monday. By 1214 GMT, it traded at $0.9233.
Against the yen, it fell 1.3 percent to a session trough of 84.48 yen, retreating from 86.20 yen hit on Monday, its strongest since September 2008.
Other commodity-linked currencies including the New Zealand and Canadian dollars also sold off after China's announcement, which triggered broad selling in gold prices.
The euro slipped 0.2 percent to $1.4485, struggling after the PBOC announcement.
Earlier in the day, it had hit the day's low around $1.4455 on the back of comments from a Chinese sovereign wealth fund official that he did not think the U.S. currency would depreciate further.
The dollar index, which tracks its movements against a basket of currencies, was 0.1 percent higher at 77.080.
(Reporting by Neal Armstrong, writing by Naomi Tajitsu; Editing by Nigel Stephenson)