Construction site safety: the hierarchy of controls, and why it decides most questions
Construction site safety assessments in New Zealand are built around three things: your duties under the Health and Safety at Work Act 2015, the hierarchy of controls, and site-specific hazard knowledge. Formats vary by provider and course, so confirm the specifics of yours.
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One concept carries more marks than any other
The hierarchy of controls. If you learn one thing before your assessment, learn this, in order:
- Elimination — remove the hazard entirely
- Substitution — replace it with something less hazardous
- Isolation — separate people from it
- Engineering controls — physical changes that reduce exposure
- Administrative controls — procedures, training, signage, rosters
- PPE — personal protective equipment
A large share of questions in any construction safety assessment reduce to: given this hazard, which control do you reach for first? And the answer is always the highest one on that list that is reasonably practicable.
The reason this catches experienced people out is that site instinct runs the list backwards. On a real job, PPE is fast, cheap and visible — hand out the harnesses and get on with it. The assessment wants you to ask first whether the work can be done without anyone going up there at all.
Both instincts are defensible on a Tuesday afternoon. Only one of them is the correct assessment answer, and only one of them is what the Act actually requires.
Duties under the HSWA 2015
The second-biggest source of lost marks, and the part you cannot reason your way through from site experience.
The PCBU — the person conducting a business or undertaking — holds the primary duty of care. Not "the boss" as an individual; the business entity.
Officers — directors and senior decision-makers — have a due diligence duty. They must actively verify that health and safety is being managed, not merely delegate it and assume.
Workers have duties too, and this is the part people miss. You must take reasonable care of your own safety, take reasonable care that you do not adversely affect others, comply with reasonable instruction, and cooperate with policy. Responsibility does not all flow upward.
Duties overlap rather than transfer. More than one PCBU can hold a duty over the same work — the main contractor and the subcontractor both. They are required to consult, cooperate and coordinate. A common assessment question hinges on exactly this: the answer is rarely "it is the main contractor's problem".
Site-specific hazards
Expect questions across:
- Working at height — the leading cause of serious harm in NZ construction; fall protection, edge protection, ladders and scaffolding
- Excavations — collapse, services, access and egress
- Mobile plant — exclusion zones, spotters, reversing, and pedestrian separation
- Electricity — overhead lines, underground services, and safe isolation
- Asbestos — where it appears in NZ buildings, and what to do when you find it, which is stop
- Noise, dust and silica — including respirable crystalline silica from cutting engineered stone and concrete
- Manual handling — the assessment, not the "lift with your legs" folklore
- Hazardous substances — safety data sheets, labelling and storage
Notifiable events
Know what must be reported to WorkSafe and what must happen at the scene. A notifiable event includes a death, a notifiable injury or illness, and a notifiable incident — and the site must not be disturbed afterwards, except to help an injured person, make the site safe, or where a Police or WorkSafe inspector permits it.
That "do not disturb the scene" duty is heavily tested and routinely got wrong.
How to prepare
Do questions before your course, not after. You get one day with a trainer. Turning up already knowing which topics you are weak on turns that day from passive listening into targeted questions.
Focus on the legal duties section. The hazard content you can partly reason through from experience. The duties, the notifiable events, and the hierarchy order you cannot.
Learn the hierarchy in order, cold. Six items. It is the highest-value memorisation in the whole assessment.
Sources
- WorkSafe New Zealand (worksafe.govt.nz) — guidance, notifiable events, industry-specific material
- Health and Safety at Work Act 2015 — legislation.govt.nz
- Your training provider — for the current format of the specific assessment you are sitting
Practise before your assessment: AllSorted's Site Safe practice test has free practice with no signup, covering legal duties, hazard control and site practice. Full access is $14.99 for three months. AllSorted writes original questions and is not affiliated with Site Safe New Zealand, WorkSafe or any training provider.
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Last reviewed: 21 August 2026
Unofficial practice only. AllSorted writes original questions. We are not affiliated with Site Safe New Zealand, WorkSafe, or any other examining or licensing body. These items are not official exam papers.