The Stock Exchange of Hong Kong yesterday stood firm and refused to extend its trading hours in line with the futures exchange.
It also reiterated its claim that different trading hours for the cash and futures markets would pave the way for renewed market manipulation.
The Hong Kong Futures Exchange (HKFE) will open 15 minutes earlier and close 15 minutes later from Friday.
The proposal was approved by the Securities and Futures Commission on Monday in the face of stiff opposition from the stock exchange.
The move will help the HKFE compete with the Singapore International Monetary Exchange (Simex), which will launch a Hong Kong index futures product on Monday.
After the change, the HKFE's trading hours will match those of Simex but will no longer be synchronised with the stock exchange.