BEIJING - China's central bank continued net cash injections into the money market Tuesday to ease liquidity strain.

The People's Bank of China (PBOC) conducted 300 billion yuan ($45.2 billion) of reverse repos Tuesday, pumping a net 80 billion yuan into the market as 220 billion yuan of reverse repos matured.

Reverse repo is a process by which the central bank purchases securities from commercial banks through bidding with an agreement to sell them back in the future.

Tuesday's operation came after a net injection of 40 billion yuan Monday, 90 billion yuan Friday and 20 billion yuan Thursday, as maturing reverse repos and tax payments put pressure on liquidity near the end of month.

Despite the injection, the overnight Shanghai Interbank Offered Rate (Shibor), which measures the cost at which banks lend to one another, climbed to 2.736 percent Tuesday from 2.72 percent Monday.

On Tuesday, the PBOC conducted 140 billion yuan of seven-day reverse repos priced to yield 2.45 percent, 60 billion yuan of 14-day contracts with a yield of 2.6 percent, and 100 billion yuan of 63-day contracts with a yield of 2.9 percent, all unchanged from previous operations.

The central bank has increasingly relied on open market operations for liquidity management, rather than cuts in interest rates or reserve requirement ratios.

China set the tone of its 2017 monetary policy as prudent and neutral, keeping appropriate liquidity levels but avoiding excessive liquidity injections.