China's interest-rate increase has less to do with the controversy over the value of its currency than with a straightforward effort to fight inflation— but it risks intensifying the currency battle nonetheless.

Many observers say China's move Tuesday to raise key rates is a textbook response to the country's strong growth, rising inflation and the risk of a dangerous property bubble. More increases are likely, they say, as China tries to slow the frenzied borrowing that helped it through the recent recession.

But the rate move—which comes just days before finance ministers and central bankers from the Group of 20 industrial and developing nations meet in South Korea—has implications for China's currency, too. In most economies, higher interest rates attract foreign investors looking for better returns. The cash flooding into the economy boosts the local currency. But China's economy is mostly closed, limiting—though not eliminating—the impact of higher rates on the yuan.

The increase in interest rates could actually complicate matters for China on the currency front, said Nicholas Lardy, a specialist in China at the Peterson Institute for International Economics, a Washington think tank. Given that Chinese interest rates were already above what developed countries are paying on one-year deposits, and that the market is betting that the yuan will rise over time, the rate increase could serve only to attract more investor money.