Sites on Google's Blogger platform have long used addresses of the form blogname.blogspot.com. Google is now applying the same regional detection it uses on its main site to Blogger, so many of those addresses will now show up in the form blogname.blogspot.com.au for Australian visitors.
Google Operating System (a blog which itself is affected by the switch) notes that the change is designed to make it easier for Google to block access to content which might be banned in a specific country. Unlike many blogging platforms, Blogger allows some adult content, which creates potential headaches for Google in some markets where that material is banned. Being able to block the country-specific version of a site allows Google to meet those requirements without taking the blog offline.
You can work around the redirect by adding /ncr to the end of the blogger address. For example, googlesystem.blogspot.com/ncr Note that this will give you the US English version of the site, regardless of your own Google language and region settings. (You can similarly use google.com/ncr to access the main Google site rather than a localised version such as google.com.au, which is where Google will send you if it detects that you're accessing the site from Australia.) The change doesn't impact Blogger sites with their own domain.
Google's support page says the country-specific blog addresses will be rolled out in various areas over the coming months, but redirection already seems to be happening for Australian users. Does the Big G now something we don't about government plans to reactivate Internet filtering?
Country-Specific Blogger URLs [Google Operating System]