* Hong Kong shares hit three-wk low, mirroring Shanghai fall
* Shanghai slips as heavy supply of new shares sparks selling
* Hong Kong stocks have further to fall - brokers
* Unicom falls on higher-than-expected iPhone retail price (Updates to close)
By Sui-Lee Wee and Lu Jianxin
HONG KONG/SHANGHAI, Sept 28 (Reuters) - Hong Kong stocks fell to a three-week closing low on Monday, dragged down by telecoms after a late tumble by Chinese shares prompted skittish investors to lock in profit, and as weak U.S. housing data raised doubts about the strength of the global recovery.
Optimism about an easing global recession had helped the Hong Kong stock market skim one-year highs in the past two weeks, but some investors questioned the strength of the rally, saying the market had run ahead of itself.
"There's nothing to latch on to now," said Howard Gorges, a director at South China Brokerage. "We've clearly entered a phase of profit-taking after the good run."
"We're going to continue to have little turnover," he said. "We've already entered something of a correction and we may have further to go. People have gotten cautious."
The benchmark index fell to as low as 20,534.82, before trimming losses to 20,588.41 at the close of trade, down 2.07 percent or 435.99 points from the previous close.
Turnover was HK$50.9 billion ($6.57 billion), compared with Friday's HK$56.41 billion.
"The outlook is quite negative," said Peter Lai, a director with DBS Vickers, citing weak U.S. economic data. "The Hang Seng Index has been overbought in the last few weeks and I expect some sort of correction to come soon."
"When the closing price of an IPO falls below the issue price, that definitely is detrimental to the sentiment of retail investors," he said, referring to last week's dismal start of trade of Metallurgical Corp of China <1618.HK>, which marked Hong Kong's worst debut this year.
The China Enterprises Index of top locally listed mainland Chinese stocks was down 2.52 percent at 11,752.65.
DBS's Lai predicted that the index could fall to 19,800 in the coming weeks and below 18,000 in the coming quarter.
China Unicom, the country's No.2 mobile carrier, fell 5 percent to a near three-week low after the company said that Apple's popular iPhone would retail in China for 5,000 yuan ($732.50), above market expectations.
The Chinese telco also said it would buy back a stake held by SK Telecom (SKT) for $1.3 billion.
Lighting manufacturer Bright International Group Ltd surged as much as 29 percent to a record high after the company said it would buy gold mines in China for a total of HK$7.41 billion to tap rising prices of the precious metal. The stock's gains later eased to trade up 4.55 percent at HK$0.69.
Huscoke Resources climbed as much as 22.5 percent to a near nine-month high of HK$0.60 after the company swung to a first-half net profit of HK$20.2 million, from a loss of HK$16.2 million a year earlier, on soaring revenue from its coal business. The stock closed up 10.2 percent at HK$0.54.
PetroChina, Asia's top oil and gas producer, fell 2.88 percent to HK$8.75, while China's top offshore oil producer CNOOC Ltd dropped 0.8 percent to HK$10.30 as oil slipped below $66 per barrel on Monday, extending last week's 8.4 percent decline.
SHANGHAI FALLS
China's key stock index closed 2.65 percent lower as falling global markets and prospects for a continued heavy supply of new shares sparked a selling spree ahead of a long holiday.
Investors actively traded stocks with corporate restructuring plans. Computer maker Tiancheng, among the biggest losers of the day, fell by its 10 percent daily limit to 21.03 yuan after it disappointed investors by saying it had given up a restructuring plan announced a month ago.
The Shanghai Composite Index finished down 75.317 points at 2,763.525 points after hitting an intraday low of 2,752.773, down 3 percent from Friday's close.
Shanghai had initially lagged Asian falls but when overseas markets showed no signs of recovering in the afternoon, investors became increasingly unwilling to keep stocks on hand ahead of the eight-day National Day holiday that starts on Oct. 1.
"Investors conducted stop-loss selling amid fears that a slump in overseas markets during the Chinese holiday could spark a market tumble after the break," said Qian Qimin, deputy research head at Shenyin and Wangguo Securities in Shanghai.
Last week, the index dropped 4.2 percent, its biggest weekly fall in six weeks, with sentiment hurt by a huge supply of new shares, including initial public offerings (IPOs).
"The essential problem facing the market now is that supply has exceeded demand, with no signs of an end to new shares coming to the market," said research manager Wu Xiong at Orient Securities in Shanghai.
Traders now expect the index to fall further before the holiday and seek support at a three-month low of 2,639.
Shanghai Construction, the day's biggest gainer, bucked the nearly across-the board market fall on Monday to jump by its 10 percent daily limit to 14.62 yuan after announcing a major corporate restructuring, which investors believe might benefit the company's long-term development.
Glassmaker Anhui Fangxing fell by the limit to 14.18 yuan after it said it would swap core glass-making assets for new business in new materials industry.
Turnover dropped to 75 billion yuan on Monday, the lowest level since March 16, from a thin 81 billion yuan on Friday, with losing Shanghai A shares overwhelming gainers by 789 to 95.
The thin trade came after a hefty 618 billion yuan in subscriptions to China International Travel Service Corp's 2.6 billion yuan IPO was freed up on Monday -- a clear indication that investors are unwilling to build fresh positions. (Editing by Chris Lewis)