Sri Lankan studying in uni Nanning wishes to visit Hong Kong. Is on arrival visa given?

My daughter is a Sri Lankan studying in a Medical Uni in Nanning, China. She has student type in China. She and few of her friends wishes to visit Hong Kong during summer vacation to see Disney Land. She holds a Sri Lanka Passport stamped with China Student type entry permit. Can she obtain an VOA because she plans to travel from Nanning via Hong Kong and to Sri Lanka. Needs to find out whether VOA is stamped in Hong Kong and for how many days.
Please let me know the procedure.
Thank you,
Yasomie Peiris (Mother)