s 4 , Workers Compensation Act 1987 – Injury:

1. means personal injury arising out of or in the course of employment,
2. includes a disease injury, which means:
   1. a disease that is contracted by a worker in the course of employment but only if the employment was the main contributing factor to contracting the disease, and
   2. the aggravation, acceleration, exacerbation or deterioration in the course of employment of any disease, but only if the employment was the main contributing factor to the aggravation, acceleration, exacerbation or deterioration of the disease, and
3. does not include (except in the case of a worker employed in or about a mine) a dust disease, as defined by the  Workers’ Compensation (Dust Diseases) Act 1942 , or the aggravation, acceleration, exacerbation or deterioration of a dust disease, as so defined.

No compensation is payable under this Act in respect of an injury (other than a disease injury except for exempt workers) unless the employment concerned was a substantial contributing factor to the injury —  s 9A(1) , 1987 Act .

NB: In the case of a disease injury, a disease contracted by a worker in the course of employment, where the employment was a contributing factor to the disease —  s4 , Workplace Injury Management and Workers Compensation Act 1998. 

Injury: an injury arising out of or in the course of any employment —  s39(1) , Workplace Injury Rehabilitation and Compensation Act 2013 

Disease: has contracted a disease specified in relation to that place, process or occupation—‘  s51(2)(b) 

Compensation is not payable in respect of the following injuries unless the worker’s employment was a significant contributing factor to the injury:

1. a heart attack or stroke injury
2. a disease contracted by a worker in the course of employment (whether at, or away from, the place of employment), or
3. a recurrence, aggravation, acceleration, exacerbation or deterioration of any pre-existing injury or disease —  s40(2) and  s40(3) .

If the worker has been employed at any place or in any process or occupation declared under s51(1) and has contracted a disease specified in relation to that place or process or occupation,  then the disease is deemed to be due to the nature of the employment at such place or in such process or occupation unless the employer or the Authority or a self-insurer, as the case may be, proves to the contrary. 

injury if (and only if) it arises from employment —  s7 , Return to Work Act 2014 

Physical injury: the injury arises out of or in the course of employment and the employment was a significant contributing cause of the injury; and

Psychiatric injury: the psychiatric injury arises out of or in the course of employment and the employment was the significant contributing cause of the injury and the injury did not arise wholly or predominantly from any action of decision designated under subsection 7(4).

‘a significant contributing cause of the injury’ —  s7(2)(a) for non-psychiatric injuries

‘the significant contributing cause of the injury’ —  s7(2)(b ) for psychiatric injuries

Injury includes a disease, and the recurrence, aggravation, acceleration, exacerbation or deterioration of any pre -existing injury or disease where the employment was the major or most significant contributing factor to that recurrence, aggravation, acceleration, exacerbation or deterioration.

Except in some circumstances ‘injury’ does not include an asbestos-related disease within the meaning of the Asbestos-Related Diseases (Occupational Exposure) Compensation Act 2011 —  s3(1) , Workers Rehabilitation and Compensation Act 1988. 

The liability of employers to compensate workers for injuries, relates to:

• An injury, not being a disease, arising out of, or in the course of employment —  s25(1)(a) 
• an injury, which is a disease, to which his employment contributed to a substantial degree —  s25(1)(b) .

To a substantial degree, that is, employment is the ‘major or most significant factor’ (for diseases only) —  s3(2A) 

Employment being the major or most significant contributing factor is also a requirement in relation to injuries that are a recurrence, aggravation, acceleration, exacerbation or deterioration of any pre-existing injury or disease ( s3(1) — in definition of ‘injury’).

An injury, in relation to a worker, is a physical or mental injury arising out of or in the course of the worker's employment and includes  a disease and the aggravation, acceleration, exacerbation, recurrence or deterioration of a pre-existing injury or disease.

Despite any other provision of this Act, a mental injury is not considered to be an injury for this Act if it is caused wholly or primarily by one or more of the following:

• management action taken on reasonable grounds and in a reasonable manner by or on  behalf of the worker's employer;
• a decision of the worker's employer, on reasonable grounds, to take, or not to take, any management action;
• any expectation by the worker that any management action would, or would not, be taken or any decision made to take, or not to take, any management action.

s3A , Return to Work Act 1986 

Out of or in the course of the worker's employment –  s4   Return to Work Act 1986 

Material contribution, (for diseases —  s4(6) and gradual process — [ s4(5)] that is employment was the real proximate or effective cause ( s4(8) ).

A mental injury is not an injury if due to management action taken on reasonable grounds and in a reasonable manner —  s3A(2) . See  s3(1) for definition of ‘management action’

For heart attack or stroke injury — material contribution —  s58 that is employment was the real proximate or effective cause —  s4(8) 

For injuries:  a physical or mental injury arising out of, or in the course of, the employee’s employment or an aggravation of a physical or mental injury (other than a disease) suffered by an employee —  s5A , Safety, Rehabilitation and Compensation Act 1988 

For diseases: an ailment or aggravation of an ailment that was contributed to, to a significant degree by an employee’s employment —  s5B  

For injuries: an injury (other than a disease) suffered by an employee, being a physical or mental injury arising out of, or in the course of, the employee’s employment’, or ‘an aggravation of a physical or mental injury (other than a disease) suffered by an employee’  s3 , Seafarers Rehabilitation and Compensation Act 1992 

For diseases: ‘any ailment suffered by an employee, or the aggravation of any such ailment, being an ailment or an aggravation that was contributed to in a material degree by the employee’s employment’ —  s3 

MRCA –  s5 ,  s27 ,  s29(1) ,  s29(2) and  s30 

An injury sustained or a disease contracted which arose out of, or was attributable to, any defence service rendered by the person while a member; or resulted from an occurrence that happened while the person was a member rendering defence service. 

Includes the aggravation of an injury, or its signs and symptoms, which was contributed to in a material degree by, or was aggravated by, any defence service rendered by the person while a member after he or she sustained the injury or contracted the disease, and/or aggravated by treatment provided by the Commonwealth.

DRCA

For injuries: a physical or mental injury arising out of, or in the course of, the employee’s employment, or an aggravation of a physical or mental injury (other than a disease) suffered by an employee —  s5A 

For diseases: ‘an ailment or aggravation of an ailment that was contributed to, to a significant degree by an employee’s employment’ —  s5B 

Minimum material contribution required (‘arose out of, or was attributable to’) — MRCA,  s27(b) and  27(c) 

In a material degree (for aggravations only) — MRCA,  s27(d) and  s30 

To a significant degree (for diseases) —  s5B , with matters to be taken into account being set out in a non-exclusive list and with ‘significant degree’ being defined as ‘substantially more than material’