Stocks in Hong Kong and the mainland tumbled on another volatile day on Wednesday after Beijing disappointed investors over a lack of fresh stimulus and scant detail on its plans for implementing a raft of measures already unveiled.

After blockbuster performances in the wake of last month's announcements to kickstart growth, traders were left deflated after a news conference on Tuesday fell short of expectations and revived worries about the outlook.

After swinging in the morning, the Hang Seng Index closed down 1.4 percent at 20,637.

Turnover reached HK$427 billion, down from a record HK$620 billion on Tuesday.

The Shanghai Composite Index closed down 6.6 percent at 3,258 and the Shenzhen Component Index finished 8.15 percent lower at 10,557.

The combined turnover of the Shanghai and Shenzhen bourses reached 2.94 trillion yuan, down from 3.45 trillion yuan the day before. (Agencies)