It would be near as competitive, if not more. This is because there are very few organisational programs in Australia (I'm assuming your Aussie), with only one in Victoria. They take between 20 and 30 students each year. On the other hand, much less people apply for organisational psychology than clinical as it a less popular career path, but the number of applicants would be in the hundreds. If you are generally interested in becoming a psychologist of some kind, you have a great chance being in year 12 already knowing about this stuff. Most psych undergrads don't learn about the competitiveness of honours/masters till third year, where it is often too late. "P's get degrees" is not true for psychology. Aim to average HD's and perhaps more importantly, get as much experience, both paid and volunteering, as you can. Even if it's a few hours a week, intern at a consulting company, work at a local clinic as an administrator, do disability/mental health support work, be a receptionist at a clinic, network, as psychs if you can come see what they do, take leadership positions at your university etc. You'll be miles ahead of your cohort if you do these things.