Quick answer: A risk matrix scores hazards by combining Likelihood (how likely harm is) and Consequence (how severe it would be) to produce a risk rating — Low, Medium, High, or Extreme. Every SWMS and risk assessment should use one to justify the controls you have chosen.
Last reviewed: March 2026 by the BlueSafe Technical Team. Reflects current Model WHS Regulations.
A Risk Matrix is a standard tool used in risk management to define the level of risk associated with a specific hazard. It helps you prioritise which risks need immediate attention and which are acceptable to monitor.
The matrix works by combining two factors: Likelihood and Consequence.
1. Likelihood (How likely is it to happen?)
You must estimate the probability of the incident occurring.
- Rare: May occur only in exceptional circumstances.
- Unlikely: Could occur at some time.
- Possible: Might occur at some time.
- Likely: Will probably occur in most circumstances.
- Almost Certain: Is expected to occur in most circumstances.
2. Consequence (How bad would it be?)
Estimate the severity of the harm if the incident did occur.
- Insignificant: No injuries, low financial loss.
- Minor: First aid treatment required.
- Moderate: Medical treatment required.
- Major: Extensive injuries, loss of production capability.
- Catastrophic: Death or permanent disability.
3. The Risk Score (L x C)
By cross-referencing Likelihood and Consequence on the grid (usually 5x5), you get a Risk Rating: Low (L), Medium (M), High (H), or Extreme (E).
- Example: A worker working on a roof without rails.
- Likelihood: Possible (slips happen).
- Consequence: Catastrophic (death from fall).
- Result: Extreme Risk.
What the Ratings Mean
- Extreme Risk: STOP WORK IMMEDIATELY. The risk is intolerable. Work cannot proceed until controls are implemented to lower the risk.
- High Risk: Urgent action required. Senior management attention needed. Controls must be implemented before work starts.
- Medium Risk: Manage by specific monitoring or audit procedures. Responsibility must be specified.
- Low Risk: Manage by routine procedures.
Residual Risk
When you perform a risk assessment, you usually score the risk twice:
- Inherent Risk: The risk level before any controls are applied. (e.g., Working on roof = Extreme).
- Residual Risk: The risk level after controls are applied. (e.g., Harness + Guard rails installed = Low).
The goal of your WHS system is to ensure that the Residual Risk for all tasks is reduced to a level that is "As Low As Reasonably Practicable" (ALARP).
Using the Matrix in Your Business
Every SWMS and Risk Assessment should utilise a risk matrix to justify the controls you have chosen. It provides a logical, defensible method for your safety decisions.
State and Territory Variations
The information on this page is based on the Model WHS Regulations published by Safe Work Australia, which have been adopted (with minor variations) by most states and territories.
| Jurisdiction | WHS regulator | Key notes |
|---|---|---|
| NSW | SafeWork NSW | Adopted Model WHS Regulations |
| VIC | WorkSafe Victoria | Uses OHS Act 2004 — some terminology differs |
| QLD | Workplace Health and Safety Queensland | Adopted Model WHS Regulations |
| SA | SafeWork SA | Adopted Model WHS Regulations |
| WA | WorkSafe Western Australia | Adopted Model WHS Regulations (2022) |
| TAS | WorkSafe Tasmania | Adopted Model WHS Regulations |
| ACT | WorkSafe ACT | Adopted Model WHS Regulations |
| NT | NT WorkSafe | Adopted Model WHS Regulations |
Always verify requirements with your state regulator, as local codes of practice and guidance may impose additional obligations.
Related guides
- Hierarchy of Controls Explained
- How to Write a Safe Work Method Statement (SWMS)
- Manual Handling Risk Assessment Guide
- Confined Space Entry: Safety Procedures
Frequently asked questions
What is a risk matrix?
A risk matrix is a standard WHS tool that defines the level of risk for a hazard by combining Likelihood and Consequence into a rating of Low, Medium, High, or Extreme. It is used in SWMS and risk assessments to prioritise which risks need immediate action.
How do I score likelihood and consequence?
Likelihood is rated from Rare to Almost Certain. Consequence is rated from Insignificant to Catastrophic. Cross-referencing both on a 5x5 grid gives your overall risk rating.
What is residual risk?
Residual risk is the risk level remaining after controls are applied. The goal is to reduce residual risk to As Low As Reasonably Practicable (ALARP).
When should I use a risk matrix?
Use one in every SWMS and risk assessment to justify your chosen controls. It provides a logical, documented method for safety decisions that SafeWork Inspectors expect to see.
Need templates with matrices built in? Get a risk management plan or risk assessment templates.