The Hang Seng Index opened more than 400 points higher before plunging.
It ended 1.06 percent or 324 points lower at 30,319.
Turnover hit HK$302.5 billion.
Tech shares took a beating, with Alibaba down 2.5 percent, Tencent giving up 3.7 percent and Xiaomi diving 5.3 percent.
Across the border, the benchmark Shanghai Composite Index shed 1.45 percent, or 53 points, to 3,642, while the Shenzhen Composite Index on China’s second exchange dropped 2.11 percent, or 51 points, to 2,416.
Regional markets were mixed. The Nikkei rose 0.46 percent on expectations of an economic recovery in Japan, while Taiwan shares put on 0.4 percent. But the Kospi in South Korea lost 0.9 percent and the Australian ASX fell 0.2 percent. (Additional reporting by AFP)