The rising number of Hong Kong homeowners with apartments worth less than their mortgages may further hurt sentiment already damped by the global equity rout and government curb, according to Barclays Capital Research.

The estimated number of mortgages in “negative equity” jumped to 1,653 at the end of the third quarter from 48 three months earlier, with the value of those loans rising to HK$4.1 billion ($528 million) from HK$58 million, the Hong Kong Monetary Authority said Oct. 28.

The number “provides the first clear evidence of the on- going decline in Hong Kong property prices,” Barclays’ Hong Kong-based analysts Andrew Lawrence and Vivien Chan wrote in a report today. “Further price falls are expected to follow.”

The threat of a global economic slowdown is intensifying risks in Hong Kong’s home market and the government will monitor housing policies designed to curb prices, said Financial Secretary John Tsang said Oct. 27. Home transactions fell for a ninth straight month in September, while prices declined 3 percent from June to August, government statistics show.

Rising negative equity “suggests that bank valuations for mortgages are falling quickly,” wrote Lawrence, who forecast home prices may drop as much as 30 percent by 2013 in an earlier report. “Homebuyers will either need to use more equity to fund their home purchases or negotiate lower prices.”

Hong Kong’s Chief Executive Donald Tsang promised to provide more affordable homes and signaled greater government intervention in narrowing social inequality in his Oct. 12 policy address, responding to a public outcry over the more-than 70 percent surge in home prices since early 2009.

The Hang Seng Property Index, which tracks the city’s seven-biggest developers, fell 1.3 percent as of 11:01 a.m. in Hong Kong, the biggest decline among the four industry groups in the benchmark Hang Seng Index. It declined 16 percent this year, compared with the 13 percent drop in the benchmark gauge.