The IR35 related laws in the UK make independent contracting much easier and therefore more common there than in Australia. As I understand it, many UK contractors would be considered employees under Australian law.

Having run my business in Australia and then the UK, I asked the founder of Crunch in the UK (Accounting support for contractors) if he planned to expand to Australia because I loved their service. While open to it at some point, iirc he said there just wasn't the volume of potential clients down under to justify the legislation and recruitment investment.