SHANGHAI, July 16 (Reuters) - China stocks held steady on Tuesday, as investors awaited the details of reform measures announced at the 'Third Plenum' meeting amid a slew of weak economic data. Hong Kong shares fell, dragged by tech stocks.

** China's economy grew much slower than expected in the second quarter as a protracted property downturn and job insecurity knocked the wind out of a fragile recovery, keeping alive expectations that Beijing will need to unleash more stimulus.

** The highly watched Third Plenum will outline efforts to promote advanced manufacturing, revise the tax system to curb debt risks, manage a vast property crisis, boost domestic consumption and revitalise the private sector. The details will likely come out on Thursday.

** Shares of China's Ping An Insurance fell 5.4% in Hong Kong, after the insurer said it had raised $3.5 billion in a convertible bond.

** At the midday break, the Shanghai Composite index was down 0.21% at 2,967.85.

** China's blue-chip CSI300 index was up 0.21%, with its financial sector sub-index down 0.54%, the consumer staples sector up 0.16%, the real estate index up 1.74% and the healthcare sub-index trading 0.17% higher.

** Chinese H-shares listed in Hong Kong fell 1.34% to 6,335.88, while the Hang Seng Index was down 1.37% at 17,769.96.

** Hong Kong-listed tech giants declined 1.7%, with Trip.com down 6.1%.

** The smaller Shenzhen index was down 0.07%, the start-up board ChiNext Composite index was higher by 0.39% and Shanghai's tech-focused STAR50 index was up 0.94%.

** Around the region, MSCI's Asia ex-Japan stock index was weaker by 0.35%, while Japan's Nikkei index was up 0.34%.

** The yuan was quoted at 7.2649 per U.S. dollar, 0.08% weaker than the previous close of 7.259.

(Reporting by Shanghai Newsroom; Editing by Rashmi Aich)