Hong Kong stocks nosedived on Tuesday, losing more than 9 percent, while mainland markets reopened after a weeklong holiday with solid gains as Beijing expressed confidence that it will meet its economic targets.

The Hang Seng Index had shed more than 5.5 percent, or nearly 1,300 points, in morning trade, and the sell-off continued in the afternoon.

The index finished the day 9.4 percent or 2,172 points lower at 20,926, the biggest drop in 16 years.

Turnover topped HK$620 billion, a fresh record high.

Losses were recorded across the board.

It was a different story on the mainland, with the Shanghai Composite Index up 4.59 percent to 3,489 and the Shenzhen Component Index putting on 9.17 percent at 11,495.

Shares had hit two-year peaks in early trade before giving up some of those gains.

At a press briefing in Beijing, the head of the National Development and Reform Commission, Zheng Shanjie, said China is fully confident of achieving economic targets for 2024 and would pull forward 200 billion yuan from next year's budget to spend on investment projects and support local governments.

But some investors were left disappointed by what they see as a lack of new stimulus. (Agencies)