Chinese shares have plummeted more than 8 per cent in morning trade, extending fears of a deep global market sell-off driven by broader concerns around the Chinese economy.

The benchmark Shanghai Composite Index ended the morning session down 296.55 points, or 8.5 per cent, at 3211.20 – prompting official news agency Xinhua to dub the day "Black Monday" even before the day was over.

Chinese shares began Monday with losses after data showed manufacturing contracted for a fifth straight month. Credit:Getty Images

The market was in freefall from the open, crashing through the 3500 point barrier – which the central government had previously said would be the market's "bottom line" of support – without resistance, and erased all year-to-date gains.

​Nearly 2000 stocks – about two-thirds of the market – hit the daily maximum 10 per cent fall allowed by the Chinese stock exchange.