* SSEC -0.7 pct, CSI300 -0.7 pct, HSI -1.2 pct
* Financials down amid tougher regulations
* Resources slump, oil prices tumble
SHANGHAI, May 5 (Reuters) - China stocks hit fresh three-month lows at midday on Friday, as investor concerns about tighter financial regulations weighed on investor sentiment while sharp falls in oil and commodities prices hit and resources shares.
The CSI300 index fell 0.7 percent, to 3,380.46 points at the end of the morning session, while the Shanghai Composite Index also lost 0.7 percent, to 3,106.10 points.
China's local banking regulators are conducting examinations on capital rotation, circumvention of arbitrage regulations and illegal transactions, the official Shanghai Securities News reported on Friday, citing insiders at the banks.
The move is one of the latest measures by regulators to contain financial risks in the nation's banking system.
"Obviously regulations are tightening and a large number of regulatory measures will come in the second half of the year, thus hurting sentiment," said Zhu Qibing, an analyst with BOCI Securities.
An index tracking banking stocks slid to a fresh nine-month low.
Investor jitters spread to other financial stocks, with many brokerage firms slumping more than 5 percent after Northeast Securities was suspended from selling financial products amid regulatory efforts to contain risks in the broader financial system.
Developers also took a hit on news Shanghai's housing regulator planned to introduce a lottery system to govern new home sales, a sign authorities are looking to slap on new property curbs.
For the day, sectors fell across the board, led by financials, and energy stocks , after a tumble in crude oil prices on Thursday erased the gains made since a production cut deal last November.
Hong Kong stocks followed other Asian markets lower on Friday, as fresh falls in commodities raised concerns about the health of the global economy.
Oil plunged to five-month lows on Thursday amid record trading volume in Brent crude, as OPEC and other producers appeared to rule out deeper supply cuts to reduce the world's persistent glut of crude.
The Hang Seng index dropped 1.2 percent, to 24,396.85 points.
The Hong Kong China Enterprises Index lost 1.9 percent, to 9,895.78.
Indexes tracking energy and material stocks dropped 2.8 percent and 2.6 percent, respectively.
Reporting by Luoyan Liu and John Ruwitch; Editing by Sam Holmes