Do I need the Transit Visa. Where in Fiji can I apply? What are the requirements?

Yes, you are required to apply one for transit purpose from Chinese embassy in Fiji. It requires:
1. filled application form (ID1003A)
2. copies of your passport information page and previous entry records (if any)
3. a recent passport photo
4. your onward air ticket from HK to your country

If the embassy takes care of your application, you will receive it on the fourth working day. If it was sent to HK Immigration Department, it takes four to six weeks.