* SSEC flat, CSI300 +0.2 pct, HSI +0.7 pct, HSCE +0.5 pct
* Mainland brokerages up on friendly supporting policies
* Hong Kong shares rise on technical rebound
By Chen Yixin and Brenda Goh
SHANGHAI, Jan 7 (Reuters) - China stocks were steady on Wednesday, with brokerage shares strengthening after the regulator said it planned to relax rules for securities firms to set up subsidiaries and on background requirements for shareholders.
"This indeed has a positive impact on the brokerage sector," said Zhang Gang, analyst at Central China Securities in Shanghai. "And the valuation for the sector has corrected in pervious days - it's time for it to rebound again."
The CSI300 index rose 0.2 percent, to 3,647.81 points at the end of the morning session, while the Shanghai Composite Index was unchanged at 3,351.93 points.
Huatai Securities rose 9.3 percent, Citic Securities jumped 5.1 percent, and Haitong Securities rose 4.7 percent.
The broader market was held back by declines in the small-caps and energy shares, with the ChinNext growth board falling 1.1 percent and PetroChina, the largest oil company by market value in China, declining 1.4 percent.
The global slide in oil prices was blamed for the decline in PetroChina shares, though brokers also noted that profit-taking was probably another reason given a sharp spike seen this week.
China CSI300 stock index futures for January were flat at 3,658.6, 10.79 points above the current value of the underlying index.
The index measuring price differences between dual-listed companies in Shanghai and Hong Kong stood at 131.29.
A value above 100 indicates Shanghai shares are being priced at a premium to shares in the same company trading in Hong Kong, and vice versa.
Total volume of A-shares traded in Shanghai was 22.41 billion shares, while Shenzhen volume was 9.60 billion shares.
Total trading volume of companies included in the HSI index was 1.2 billion shares.
Hong Kong shares edged up on Wednesday, shrugging off any negative impact from losses on the U.S. markets.
The Hang Seng index rose 0.7 percent, to 23,653.95 points, while the Hong Kong China Enterprises Index was up 0.5 percent at 12,044.53 points.
"The Hang Seng index was falling towards its 250-day average on Tuesday, therefore it needed to have some technical rebound," said Sam Chi Yung, strategist at Delta Asia Financial Group in Hong Kong.
Casino shares rebounded and performed strongly in the morning session.
China Rare Earths Holdings Ltd rose for the third consecutive day in the morning session after China scrapped a quota system aimed at restricting exports of rare earths, official Chinese media reported on Monday.
New A-share account openings bit.ly/1wvJ9S9 (Editing by Shri Navaratnam)