Taken from FirstAidInternational.com.au

Legal Issues in First Aid
The following should only be used as a guide and you should seek legal advice if you have any specific issues related to first aid. First aiders are not expected to be perfect, and unfortunately it is not expected that every incident will turn out perfectly.

What is required of a first aider? They should be responsible and prudent and act in good faith for the best interests of the casualty and undertake first aid 'to the best of their ability'.

The four main considerations for first aid are:
Consent:
Australian law is based on the premise that a person has control over their own body and a person can bring a charge of assault/battery if touched without consent.
Essentially, an injured/ill person has the legal right to refuse any assistance or reject any advice from a first aider, Ambulance Paramedic, Nurse or Doctor.

The injured or ill person also has the right to see a doctor of his/her own choice at any time.

In an emergency situation, the law will imply consent of the injured or ill person if they are unconscious and seriously injured, eg bleeding. This consent will only apply to conditions that imperil the life or future health of that person.

Infants/small children: In an emergency situation, a person may take 'reasonable action' even without formal consent, which will be viewed as being acceptable in the normal conduct of life.

In relation to a minor, because they cannot give consent, if possible the consent of a parent or guardian should be obtained.


Duty of Care:
Under Australian Law a member of the public or first aider in the community, usually has no legal duty of care requiring them to stop and render assistance to an injured/ill person. This is from a legal viewpoint rather than a moral one. There are however, instances where the first aider/member of the community is obliged to stop and render assistance. For example:

A driver of a motor vehicle involved in a vehicle accident, is required to stop and render assistance to any injured person involved in that accident, to the best of their ability. This is regardless of any first aid training that person may or may not have.
Where an employee is trained and is designated as a first aider in the workplace, and receives remuneration accordingly, that employee would have an obligation to render assistance as required.
When a person trained in first aid has taken responsibility for another individual eg Child Minding.
It should also be noted that once a person begins to render assistance, there exists a legal duty of care for the physical well being of the injured/ill person in their care. A first aider's duty of care cannot be evaded by abandoning assistance half-way through.

In the case of the workplace, this duty of care takes precedence over any authority, which an employer may have over the first aid employee, or the injured/ill person.

Naturally, if an Ambulance Paramedic, Nurse, Doctor or other person with better qualifications than you arrive, it may be sensible to allow them to take over and you assist where appropriate.


Negligence
A case of negligence would be established if:

The first aider owed a 'duty of care' to the injured/ill person
The standard of care required by that duty was breached.
Further injury was sustained
The further injury was sustained because the first aider has gone beyond their level of training.
All the above factors must be proven to establish negligence. If further injury occurs in the process of removing a casualty from immediate danger/hazard in an attempt to save their life, or even more serious injury, you will have met your duty of care by undertaking a reasonable and prudent act in good faith for the best interests of the casualty.

A first aider with basic training could be expected to:

Use reasonable care in assessing the priorities of the situation in accordance with their training and take steps to call for medical assistance
Keep the casualty stabilised until help is available
Follow recommended first aid guidelines
Not misrepresent themselves or take undue risks
Special Note:
Any hesitant first aider needs to realise that any person who needs CPR because they are unconscious, not breathing cannot be worse off than that, eg dead. A casualty, who does not receive appropriate emergency medical care, including CPR, will die. Therefore, if CPR fails to restore life, the casualty will not be worse off than before. A casualty who survives will have nothing to complain about - even if the CPR caused some physical injury such as broken ribs. The alternative was death.


Recording
It is good practice to record in writing the details of any first aid you provide at an incident. This information may become necessary if the incident is brought to court. In the workplace, it is a requirement to record all incidents even where first aid was not applied. This will allow the employer to keep good record keeping, look at safety factors at work and place in new safety requiredments if required.