Dear Raj
Greeting from Peggy Top China Travel. Thanks for visiting our site.
Firstly, let me express my sincerely sorry to offer you a late reply
The following guide may help you to know about application China mainland visa in Hong Kong:
Because you want to visit Shanghai and Shenzhen which are two cities in China mainland, a visa for entry in to China mainland is needed.
When you arrival Hong Kong, you can go to the CTS Hong Kong agency (branches spreading the whole Hong Kong) to continue your China visa application process.
Here we offer you a link to know more about how to apply when you have already in Hong Kong http://www.ctshk.com/english/useful/chinesevisa.htm
Their service hot line and mail:
For enquiries, by telephone: (852) 2315 7171, by email: enquiry@ctshk.com.
Hope it is clear for you
Have a nice day!
Peggy
TopChinaTravel
Your Faithful Partner & Friend in China
Address: CITS Mansion, No.11, Binjiang Road, Guilin 541002, P. R. China
Tel: (86)773-2885326 Fax: (86)773-2805303
We are proud to be an official member of ASTA, IATA, PATA, USTOA