You can also take a look at
http://www.aacircle.com.au/forums/te...visa+hong+kong
The below has been pasted from
Hong Kong Visa and Passport entry requirements, Hong Kong Travel Guide.
Entry requirements for Americans: United States citizens must have a valid passport, but no visa is required for a stay of up to 3 months.
Entry requirements for UK nationals: British citizens must have a valid passport for intended period of stay. No visa is required for a stay of up to 6 months, provided the passport is endorsed British Citizen. No visa is required for a stay of up to 3 months depending on the place of issue of passport if the passport is endorsed British Subject or British National (Overseas) or British Overseas Citizen, or British Dependent Territories Citizen.
Entry requirements for Canadians: Canadians must have a valid passport, but no visa is required for a stay of up to 3 months.
Entry requirements for Australians: Australians must have a valid passport, but no visa is required for a stay of up to 3 months.
Entry requirements for South Africans: South Africans must have a valid passport, but no visa is required for stays of up to one month.
Entry requirements for New Zealanders: New Zealand citizens must have a valid passport, but no visa is required for a stay of up to 3 months.
Entry requirements for Irish nationals: Irish nationals must have a valid passport, but no visa is required for a stay of up to 3 months.
Passport/Visa Note: All passports must be valid for at least 1 month after period of intended stay. All visitors must be in possession of onward or return tickets, except when in transit to mainland China or Macao, as well as all documents required for next destination, and sufficient funds to cover their stay in Hong Kong.