GST Registration for E-Commerce Seller

Dear Members,
one of my clients is in the business of import and export. 
He Imports Tea and then sells it in the local market and he also has the GST Registration for the same.
Now he wants to do the same business through an E-commerce website. (i.e. he wants to sell through an E-Commerce website)
My query is does he need to obtain a fresh GST Registration?

or he can do amendments in the GST registration which he already has?