* HSI +0.3 pct, H-shares +0.8 pct, CSI300 +0.3 pct
* HK hit by series of profit warnings, could stall rally
* AIA top HSI boost, a reliable earnings play
* Great Wall Motor tests all-time high after earnings beat
By Clement Tan
HONG KONG, Jan 22 (Reuters) - Hong Kong shares held around a 19-1/2 month high for a third session on Tuesday, while onshore China markets were on track to gain for a fourth-straight day, helped by strength in the financial sector.
However, lower volumes pointed to caution as benchmark indices run into chart resistance after a fast start to the year, and amid a growing number of profit warnings ahead of the corporate earnings season.
The Hang Seng Index was up 0.3 percent at 23,657.4 at midday on Tuesday, with chart resistance around 23,708, its high on May 31, 2011. The China Enterprises Index of the top Chinese listings in Hong Kong climbed 0.8 percent.
In the mainland, the CSI300 of the top Shanghai and Shenzhen listings rose 0.3 percent, while the Shanghai Composite Index inched up 0.1 percent.
"Earnings are clearly a risk, but I won't get too worried right now. I would take some profit and rotate my money into names that are laggards and have less chance of earnings disappointment," said Hong Hao, Bank of Communication International's chief strategist.
Asian insurance giant AIA Group was the top boost to the Hang Seng Index, rebounding 1.4 percent from Monday's one-month low.
AIA is still seeing earnings forecast upgrades, with two of 20 analysts raising their earnings per share expectations by an average of 4.8 percent in the last 30 days, according to Thomson Reuters StarMine.
By contrast, 10 smaller companies issued profit warnings on Monday night.
Vanke Properties Overseas slumped 6.8 percent after warning it expects a "significant decrease" in full-year net profit, due mainly to the purchase in May of a Hong Kong-based property company by its parent China Vanke Co.
Shares in China Vanke, however, rose sharply for a second day after the company said on Monday its foreign-currency B-shares would move to Hong Kong. The B shares again rose by their 10 percent daily limit, while its yuan-denominated A shares jumped 6.1 percent.
The broader mainland market property sector eased as investors took profit after a period of outperformance.
Among companies that have already posted earnings, shares of Great Wall Motor jumped 2.7 percent in Hong Kong, testing an all-time high in early trade, and 4.7 percent in Shanghai.
China's top manufacturer of sport utility vehicles and pick-up trucks said on Monday night its net profit for full-year 2012 jumped 65.7 percent from a year before, trumping forecasts