I believe HK is 220v mains. Australia is 240v, any idea if Australian appliances will work of 220v mains? I know 220 works fine off 240 from experience.
They will work. Appliances either do 220-240 or 110-120 (and sometimes both) depending on country. Look at the electrical info panel on your appliance and it will typically say something like 220~240.
There are no separate power supply components for Australia or HK or Sweden. The variations you get from your power socket are bigger than 20 volts anyway (ever seen your lights waver when you turn on a coffee maker or toaster?) so equipment is built to cope.