I've noticed in a lot of proceedings that Aboriginal citizens in Australia are referred to as 'Aboriginal peoples', not 'Aboriginal people' - is there any specific reason?
The difference between using people and peoples isn't specific to Australian native Aborigines, it's an English distinction.
2.treated as singular or plural
The members of a particular nation, community, or ethnic group.
‘the native peoples of Canada’
Oxford Living Dictionaries
I don't think the definitions explain the distinction exactly. For example, the different groups of a community may not exactly be peoples. I'll try and explain and offer a rule that I find intuitive.
Peoples is a plural form of people that is used in specific cases. If you see a group of people standing to your left and another standing to your right you nearly never call them peoples; all together they are just people.
You use "peoples" when you're referring to more than one group that you can refer to as "a people." So a group standing on the street isn't "a people", however Cherokee American natives are "a people", the Muscogee are also "a people", and the Chickasaw are also "a people". Therefore you call them "native peoples of southeastern Unites States."
So a hint, if it helps at all, is whether you can refer to a group of people as "a people", then multiple of them are "peoples".
The people of the world
Would generally refer to the 7.6 billion individuals on Earth.
The peoples of the world
Would refer to the distinct ethnic, racial, cultural, national or whatever other groups of people. So we can talk Germans, Francophones, Hindus, Jewish, Catalonians etc.
Notice these groups can be national, linguistic, religious, ethnic, regional, etc.
It's people, not peoples. Because the people is already plural.