Attending A Research Conference in Hong Kong

Nilmi, you can apply directly from Chinese embassy in your country. The required documents are:
1. a recent 48mmX33mm photo.
2. filled ID1003A form.
3. other required documents by the embassy, such as round-trip air tickets and hotel reservation in HK.　　

If the embasssy takes care of your application form, you will get it on the fourth working day. If you application needs to be processed by HK Immigration Department, you need to wait around a month.