China's central bank nudged money market interest rates upward on Thursday just hours after the Federal Reserve raised the U.S. benchmark, as Beijing seeks to prevent destabilising capital outflows without hurting economic growth.

Economists were surprised by the move but said at just five basis points, the increases were small and more symbolic than substantive.

The People's Bank of China called it a "normal market reaction" to the Fed that would keep interest rate expectations reasonable and help with the deleveraging campaign.

China's major stock indexes declined modestly after the news, with infrastructure, IT and financial shares down.

The PBOC increased rates on reverse repurchase agreements, or reverse repos, used for open market operations by 5 basis points for the 7-day and 28-day tenors.

It also said in a statement it increased rates on its one-year medium-term lending facility (MLF) also by 5 basis points.

Thursday's move was the first time the Chinese central bank has raised rates since March, but market interest rates have risen on their own during the interim as the government pursues a range of policies to lower leverage and debt in the economy.

Chen Ji, an analyst at Bank of Communications, said the rate increase was unexpected but too small to have much meaningful impact, and represented only a response to the Fed's rate hike.

"(It) doesn't really impact borrowing costs, and fluctuations of this level are very normal in the interbank market," he said, adding that he thought China's economy was not robust enough to handle a benchmark rate increase.