The Hang Seng index fell more than 2 percent, while the Hang Seng Tech index fell 3.17 percent.
Asia-Pacific shares slumped, led by Hong Kong shares.
In mainland China, the Shanghai Composite lost 0.39 percent after the “Golden Week” holiday, while the Shenzhen Composite fell around 1 percent. The S&P/ASX 200 fell another 1.63%.
Markets in Japan, South Korea, Taiwan, and Malaysia are closed Monday for a holiday.
Later this week, the Bank of Korea will announce its benchmark interest rate decision, Singapore will release its GDP forecast for the third quarter, and China will release inflation data.
Taiwan Semiconductor Manufacturing Company and Japan Fast Retailing will report their earnings, and the U.S. will release inflation data for September.
Key U.S. stock indexes fell more than 2 percent on Friday after data showed the unemployment rate fell in September, sparking fears that the Fed will continue to raise rates aggressively.