* CSI300: -0.2 pct; SSEC: flat; HSI: -0.9 pct;
* China c.bank says China's financial risks under control
* Vanke shares fall to fresh 4-month low amid power struggle
SHANGHAI, June 28 (Reuters) - Stocks in China and Hong Kong fell on Tuesday as investors braced for the global financial and economic fallout from Britain's vote to leave the European Union.
China's blue-chip CSI300 index fell 0.2 percent to 3,114.08 points by the lunch break, while the Shanghai Composite Index was unchanged at 2,894.50.
In Hong Kong, the Hang Seng index fell 0.9 percent to 20,050.93, while the Hong Kong China Enterprises Index declined 1.3 percent.
HSBC, Europe's biggest bank, fell 1.4 percent as analysts downgraded earnings forecasts for the sector.
Mainland stocks have been less vulnerable than Hong Kong shares to the Brexit shock, partly due to China's strict capital controls. But any resulting economic slowdown in Europe would weigh further on China's exporters.
The People's Bank of China said late on Monday that the country's debt and financial risks were under control, and that the central bank continue to implement prudent monetary policy and proactive fiscal policy.
However, PBOC pointed out that a slowing economy hurt profitability of China's listed companies last year, and they may face growing operational pressure going forward as global economic situations get more complicated.
Chinese investors also got some relief on Tuesday as the yuan showed signs of steadying after hitting 5-1/2-year lows the previous day.
Premier Li Keqiang also sought to reassure nervous on Tuesday.
"It's hard to avoid short-term volatility in China's capital markets, but we won't allow roller-coaster rides and drastic changes in the capital markets," said Li, speaking at the World Economic Forum (WEF) in the city of Tianjin.
Most sectors, including resources and transportation shares were down, but small caps were firm. Shenzhen's start-up board ChiNext rose 0.7 percent.
Hong Kong shares took another step down, after Wall Street saw its worst two-day drop in about 10 months.
Telecoms was the only main sector in Hong Kong that managed to stay in positive territory by midday as investors looked for more defensive plays.
Hong Kong-listed shares of China Vanke Co Ltd fell more than 2 percent to a four-month low, after the developer said newly unveiled plans by its largest shareholder to oust its board were threatening the health of the company.
Reporting by Samuel Shen and Nathaniel Taplin; Editing by Kim Coghill