Hong Kong shares closed lower on Friday, ending the week at a 15-month low as Shanghai posted its worst weekly loss since 2011 after weak manufacturing data stoked fears about the slowing economy.

The benchmark Hang Seng Index lost 1.53 percent, or 347.85 points, to finish the day at 22,409.62 -- its lowest since May 2014 -- on turnover of HK$118.28 billion (US$15.26 billion).

Hong Kong is now down more than 20 percent from its April peak, taking it into a bear market by some definitions of the term.

"Investors aren't going to buy even with current cheap valuations," said Khiem Do, the Hong Kong based head of multi-asset strategy at Baring Asset Management.

"We need to see positive drivers, such as more aggressive monetary easing from China or the deferral of a (US Federal Reserve) rate hike," he told Bloomberg News.

Shanghai shares closed down 4.27 percent, bringing losses for the week to more than 11 percent on worries over the flagging economy and the possibility of weaker government support for equities.

China's benchmark Shanghai Composite Index plunged 156.55 points to 3,507.74 on turnover of 450.6 billion yuan ($70.6 billion), but managed to end just above the key 3,500 point mark.

It closed at almost exactly the same level as the bottom of a recent market rout on July 8 -- before Beijing stepped in with a vast rescue package -- when it ended at 3,507.19 points.

The Shenzhen Composite Index, which tracks stocks on China's second exchange, slumped 5.39 percent, or 116.09 points, to 2,039.40 on turnover of 418.8 billion yuan. It fell 11.73 percent over the week.

The slump came after data Friday showed Chinese manufacturing activity slipped to its worst level since March 2009, adding to concerns about the economy that were heightened by the surprise devaluation of the yuan last week.

The preliminary reading of Caixin's Purchasing Managers' Index (PMI) came in at 47.1 in August, falling from July's final reading of 47.8. A figure above 50 indicates growth, while anything below signals contraction.

"The weak PMI figure released today weighed on market sentiment as investors are concerned about the weakening economic performance," Zheshang Securities analyst Zhang Yanbing told AFP.

"Investors panicked after the market fell to the previous low point during the July slump," he said.

Brokerage firms fell in Shanghai. China Merchant Securities dropped 8.52 percent to 17.82 yuan while Citic Securities plunged 7.85 percent to 18.20 yuan.

Energy giants lost ground on weak global oil prices. In Shanghai, PetroChina fell 3.10 percent to 10.00 yuan and Sinopec gave up 2.14 percent to 5.48 yuan.

In Hong Kong, Air China slumped 8.92 percent to HK$9.39 while China Southern lost 2.96 percent to HK$5.58 as investors fretted the yuan fall will deter Chinese holidaymakers and make their dollar-priced debt more expensive.