question about Hong Kong visa

I applied for Hong Kong visa from Sydney. I live in Australia and have an Australian PR. I'm currently visiting Sri lanka before my intended travel to Hong Kong. I today received an email informing I was offered an entry permit to travel Hong Kong.
Can I get it stamped from Colombo consulate? Or can I get it at Hong Kong airport? If I cannot do either do I need to apply for a new one from Colombo?
Thank you
Kumudu