In Australia, you have to have a reason to fire someone, unless your company is small (<25 people?). That reason can be a great variety of things, but if they haven't done anything that you can pin on them as 'dismissably wrong', you can retrench their position instead. This is a way of saying "it's not you, it's us", but the catch is that you can't hire someone else to do that role for 6 months, ie: you're being held to your claim of 'downsizing'.