Normally there is a small price deviation from retailer to retailer. You won't see the same price at two different retailers. One will have it for $10 more, one will have it for $10 less. That's just how it goes. Nintendo Australia will give the retailers an RRP (Reccomended Retail Price) which should take into account all the expenses associated with acquiring and selling the console.
These costs include factors like wages for the employees, transit insurance, business insurance, import taxes and numerous other factors. Each retailer will have different factors affecting them so it is unreasonable to assume there will be a generalised price across the country.
Hope that makes sense!