Nothing can be done for private use, there is no government body to regulate (this can't change, our government does not have a process for this).
Workcover, Worksafe (the regulator) etc: WHS Act 2011 and the WHS Regulation 2012 stipulate that risk needs to be managed (to put it super simply!). An employer ( a PCBU - Persons Conducting a Business or Undertaking) needs to provide a safe workplace, supervision and training / instruction. These three points are the most commonly, and easily prosecuted against.
There's a few changes due in Jan 1st 2012, when the harmonisation legislation is implemented. Currently each state and territory has similar but different pieces of legislation. NSW is currently the OHS Act 2000 and the OHS Reg 2001 (though to fast track some of the changes a few sections have been 'bridged', due diligence for officers for example).
So to put it very simply; if an employer failed to provide PPE for an employee using a chainsaw the employer could very easily be prosecuted (come Jan 1 there doesn'teven need to be an incident) - what is reasonably practicable? Is it reasonable to expect an employer to provide chaps, safety glasses gloves and steel caps for an employee tasked with using a chainsaw? Is it practical for an employer to provide this and 'wear the costs associated = Yes.
There's a few ways to get to the result, a risk assessment (which is required for any task deemed 'hazardous' and I would certainly classify chainsaw use as hazardous) would identify the risk, appropriate controls would be the use of PPE to minimise the risk of harm, along with training etc.
I could go on forever, I love this stuff.