* Two plots of land sold at prices that exceed forecasts
* Cheung Kong Holdings wins both bids
* Market watches for more tightening measures (Adds details, quotes)
By Lee Chyen Yee and Joy Leung
HONG KONG, Aug 17 (Reuters) - Hong Kong auctioned two pieces of land on Tuesday at prices that trounced expectations, sparking concern that overheating may continue to threaten the property market even after the government's recent cooling measures.
The auctions, the government's fifth so far this year, came during stock trading hours and helped push up the property sub-index .HSNP more than 1 percent before easing to end 0.5 percent higher, outperforming the Hang Seng Index's .HSI 0.12 percent gain.
The land sales come just days after the government tightened mortgage lending for bigger flats, which caused transactions to more than halve over the weekend. [ID:nTOE67C067]
Hong Kong faces the threat of asset bubbles in its economy, similar to other Asian markets such as China where prices in first-tier cities have risen sharply, and India, where land prices are also surging. [ID:nTOE67F08X] [ID:nSGE675055]
"This shows that developers think the latest measures won't affect the property market in the medium to long term," said Adrian Ngan, an analysts at CCB International. "The government's latest policies are additions to what it announced earlier. It seems to have curbed some speculation in the short term, but I'm not ruling out more measures if prices still don't come down."
Ngan said he expected property shares to be well supported in the coming day or two because of the auction results.
Hong Kong auctioned a site in Ho Man Tin, Kowloon, for HK$4.1 billion ($526 million). A Reuters poll of nine analysts had expected the 78,857-sq-ft (7,326-sq-m) site, which they said offered a gross floor area of 394,285 sq ft, to sell for HK$3.73 billion.
Another site in Hung Hom, Kowloon, was auctioned for HK$3.51 billion, beating estimates of HK$2.43 billion. The Hung Hom plot was 81,279-sq-ft, offering a gross floor area of 365,756 sq ft.
Cheung Kong (Holdings) Ltd (0001.HK), owned by Hong Kong billionaire Li Ka-shing, won the auctions for both plots. Its shares ended Tuesday up 1.1 percent.
"It so happened that the two pieces of land have excellent views and our colleagues have good developments plans for then," Cheung Kong Vice-Chairman Victor Li told reporters after the auction. "I don't think the auction prices are an indication of our outlook for property prices."
A combination of low interest rates, ample liquidity and sound economic growth have pushed Hong Kong residential property prices up by almost 15 percent this year, after gaining a third last year.
Hong Kong Financial Secretary John Tsang said last week that prices for large flats had exceeded previous highs in 1997 and were headed towards historic peaks, prompting the government to raise stamp duty on luxury apartments earlier this year and implement more measures last week.
"Honestly speaking, from what we have seen over the weekend, viewing appointments and transactions have been slowing in the mass and high-end residential market," said Ricky Poon, executive director at real estate services firm Colliers.
"Transaction volumes are going to slow in the next two to three weeks, but once sentiment changes they are going to go up again," Poon said, adding that he saw prices staying flat to rising as much as 10 percent over the next 6-12 months. (Additional reporting by Donny Kwok; Editing by Chris Lewis) (See www.reutersrealestate.com for Reuters' global service for real estate professionals)