Two exclusive luxury Hong Kong real estate developments launched last week have been snubbed by buyers, with only a fifth of the apartments sold, the worst performance so far this year, according to media reports.

Just 58 of the 285 flats on offer through the New World Development's The Riverpark and Sino Land's joint venture development, Providence Peak, were bought, according to a report in the South China Morning Post. 

As a result of the lacklustre demand, New World on Sunday released another 315 flats at prices around 9 per cent cheaper than the first round, as low as HK$5.2 million ($670,000). Sizes range between 660 square feet and 964 square feet. 

"This was the poorest sales performance so far this year. It will send a negative signal to the market," said Sammy Po, a director of Midland Realty, quoted in the report. He added that it could dissuade others from buying as more investors wait on the sideline to ride out the uncertain economy. 

One factor said to be causing sluggish demand is a drop-off in appetite from Mainland buyers, who up until now have been leading sales. Home seekers are becoming more cautious ahead of possible new cooling measures when chief executive Leung Chun-ying takes seat next month.