HONG Kong's home sales have suffered their biggest drop by volume in almost nine years.

The number of residential units that changed hands in the city last month slumped 58.1 percent to 4,719, according to the Land Registry. That's the largest drop since November 1999 and the fourth straight month of declines, Bloomberg News said.

By value, sales of residential units dropped 63 percent from a year earlier to HK$16.3 billion (US$2.1 billion).

The economic outlook, coupled with declines in the Hong Kong stock market, has curbed demand for real estate and led potential buyers to expect cheaper prices. The Hang Seng Index has dropped 48 percent this year.

Prices on Hong Kong island, which houses some of the world's most expensive apartments, had their biggest weekly drop in the week ended October 19, according to Centaline Property Agency.