Hong Kong property transactions fell 12 percent in 2015, government data showed on Thursday, underscoring fears about an economic slowdown in the Asia financial centre even as it faces a growing drag from cooling activity in China.

Hong Kong's property prices remain among the highest in the world, although they have eased since September and analysts expect a further decline this year.

Property-related businesses account for nearly a fifth of the city's economic output and are a major component of individual wealth, according to ratings agency Fitch.

The total number of domestic sale and purchase agreements received by the Land Registry last year fell 12.3 percent to 55,982, according to data from Hong Kong's Rating and Valuation Department.

The total consideration for those transactions fell 3.9 percent to $417 billion.

Sales transactions for January showed a decline of more than 60 percent, the Land Registry reported this week.

"The middle class is aware that the economic downturn will affect their income," said Centaline Property Agency senior associate research director Wong Leung Sing.

"The significant case is HSBC, which stopped increasing salaries. Other big companies will follow so the middle class cut their expenses."

"They move from high rent to lower rent or negotiate with their landlords," said Wong, who doesn't see any near-term improvement. ""They don't want to buy, even if they already had plans to buy."

HSBC is a major employer in Hong Kong. It is imposing a hiring and pay freeze across the bank globally this year as it pushes through plans for annual cost savings of up to $5 billion by 2017.

Slower sales are showing up in company results.

Hang Lung Properties Ltd, which reported full-year 2015 earnings last week, said it had sold just 63 apartments and some car parking spaces last year.

Its profit plunged 57 percent and its chairman said he does not see a bottom to China's economic weakness.

Investment bank UBS forecast earlier last month that Hong Kong home prices would fall by as much as a quarter by the end of 2017.

The Hong Kong Monetary Authority (HKMA) last week said a regular survey it conducts was showing residential mortgage loans with negative equity for the first time since Sept. 2014.

As of the end of December, there were 95 loans with negative equity of a combined HK$418 million, HK$12 million of which was unsecured.

So far, Hong Kong mortgage rates have remained stable despite the fact that the Hong Kong dollar is pegged to the U.S. dollar and the Fed at the end of last year hiked U.S. rates by 0.25 percent.

Hong Kong Financial Services and Treasury Secretary KC Chan said in January that despite the rate hike, retail property demand was continuing to outstrip supply.

From a year earlier, the economy expanded 2.3 percent in the third quarter, slower than 2.8 percent growth in the second quarter.