The benchmark Shanghai Composite Index sank 76.46 points, to 3,109.95, while the Shenzhen Composite Index, which tracks stocks on China's second exchange, plunged 3.50 percent, or 69.30 points, to 1,909.42.
China's consumer price inflation came in at 1.6 per cent in December, the government said on Saturday, well short of the government's target of "around three per cent".
In Hong Kong the benchmark Hang Seng Index slipped 2.45 per cent, or 501.08 points, to 19,952.63 by lunch.
Shanghai shares closed higher Friday after authorities reversed course and suspended a new "circuit breaker" mechanism that had fuelled a global rout by twice automatically closing Chinese markets early.
"China's equity and currency markets remain very volatile even after the authorities have attempted to stem price movements," Moody's Investors Service said in a commentary on Monday.
Beijing is seeking to transition the country's growth model away from reliance on exports and fixed-asset investment towards a consumer-driven economy, but the reform is proving bumpy.
