* HSI -1.8 pct, H-shares -2.5 pct, CSI300 -0.5 pct
* Sinopec down but above HK$8.45 per new share price
* Coal, railway strength limit A-share losses
By Clement Tan
HONG KONG, Feb 5 (Reuters) - Hong Kong shares tumbled to a three-week low on Tuesday, dragged down by a 7 percent slump for China Petroleum and Chemical Corp (Sinopec) after the oil giant launched a $3.1 billion new share placement.
Wall Street's worst day since November and renewed worries that a political shake-up could disrupt the euro zone's efforts in resolving its debt crisis combined to trigger broad profit taking in the on- and offshore Chinese market.
At 0230 GMT, the Hang Seng Index was down 1.8 percent at 23,263.9, its lowest intra-day level since Jan. 15. The China Enterprises Index of the top Chinese listings in Hong Kong slid 2.5 percent.
On the mainland, the CSI300 of the top Shanghai and Shenzhen A-share listings inched down 0.5 percent, while the Shanghai Composite Index lost 0.8 percent.
"There're some liquidation of long positions today, but people are not panicking," said Alex Wong, director of asset management at Ample Finance.
"I won't rush to buy on the dips yet. It might be a better idea to see how the market consolidates from here," Wong added.
Sinopec sold 2.85 billion new Hong Kong-traded shares at HK$8.45 each, a 9.5 percent discount to Monday's close. A source familiar with the matter said they were sold to a group of about 10 investors that included some of the world's largest institutional investors and global fund managers.
Its shares dived 7 percent to HK$8.69, its lowest since end-December in Hong Kong but held above the placement price.
Its Shanghai shares fell 3.4 percent, sinking into negative territory for the year after three straight annual losses.
China Minsheng Bank slid 4 percent from Monday's record close in Hong Kong, but extended its meteoric gains in Shanghai, rising 0.8 percent.
COAL, RAILWAY COUNTERS STRONG
Losses in the onshore Chinese market were limited by strength in coal stocks with investors welcoming a local press report that Beijing plans to encourage mergers to form conglomerates in the sector.
China Shenhua Energy Co Ltd rose 1 percent in Shanghai, while smaller rival Yangquan Coal rose 3.3 percent and Datong Coal jumped 6.3 percent.
The official China Securities Journal newspaper reported that Beijing will likely introduce a development plan for 120 ports, which could drive tremendous investment in infrastructure there with a focus on transportation and energy pipelines.
Railway and subway shares rose, with CSR Corp jumping 5 percent in Shanghai and 1.1 percent in Hong Kong, while China Railway Construction gained 1.9 percent in Shanghai and 0.9 percent in Hong Kong.