Excavation work should not start until the ground, services, nearby structures, plant movements, access and emergency arrangements have been considered together. The right controls depend on the actual site—not just the planned depth of the hole.
Excavation work includes making, filling or partly filling an excavation. Common examples include trenches, shafts, tunnels, footings, service pits and other openings formed by removing soil or rock. Under the national Model Code, work connected with an excavation is construction work.
Information current: 4 August 2026.
Why excavation work is high risk
A collapsing excavation can bury or crush a person with little warning. Even a trench that looks firm may change after rain, drying, vibration, loading near the edge or disturbance during work.
Other common hazards include:
- falls into an open excavation
- workers being struck by excavators, trucks or moving attachments
- damage to underground electrical, gas, water or communications services
- spoil, materials or plant loading the excavation edge
- water entering or building up in the excavation
- hazardous atmospheres, dust, fumes or buried contamination
- instability affecting nearby buildings, roads, retaining walls or services
- falling materials and unsafe entry or exit.
The seriousness of these hazards means barriers, PPE and verbal instructions alone are rarely enough.
What should be sorted before work starts?
Pre-start planning should involve the people who understand the work and the site. Depending on the excavation, this may include the builder, excavation contractor, supervisor, plant operator, relevant subcontractors, service owners, designer and a geotechnical or structural engineer.
The planning discussion should cover:
- soil type, previous fill, moisture and groundwater
- expected depth, shape and duration of the excavation
- underground and overhead services
- nearby buildings, roads, trees and other loads
- spoil and material placement
- plant operating zones and pedestrian separation
- safe access, edge protection and site security
- weather, drainage and dewatering
- interaction with other trades
- inspection responsibilities and stop-work triggers
- emergency response and rescue arrangements.
Service information should be obtained and checked against site conditions before digging. Plans and electronic searches are important, but they should be supported by suitable locating and verification methods for the work.
Controls and documents commonly used
Controls should focus first on eliminating the need for people to enter an excavation where reasonably practicable. Where risks remain, suitable measures may include benching, battering, shoring, shielding or another engineered ground-support system.
Other controls commonly include secure barriers, covers or edge protection; safe ladders, ramps or steps; traffic management; plant exclusion zones; dewatering; ventilation or atmospheric monitoring; and keeping spoil, materials and equipment away from the edge.
The documents needed will depend on the site and scope. They may include:
- a site-specific SWMS for applicable high risk construction work
- excavation or task risk assessments
- service plans and locating records
- engineering or geotechnical advice
- traffic and pedestrian management arrangements
- permits to excavate
- inspection records and pre-start briefings
- emergency and rescue procedures.
Documents should match the excavation method, plant, workers and surrounding conditions. They also need to be communicated and used at the workface.
When does a SWMS commonly apply?
Under the national Model Code, construction work in or near a shaft or trench deeper than 1.5 metres, or in or near a tunnel, is high risk construction work requiring a SWMS. Other high risk construction work triggers may also apply, including work involving a risk of a person falling more than two metres, powered mobile plant or certain service-related risks.
A SWMS should identify the relevant high risk construction work and hazards, describe the controls, and explain how those controls will be implemented, monitored and reviewed. It should be prepared before the high risk work starts and developed with the workers who will carry it out.
Local definitions and requirements vary. Check the current WHS regulator material for the state or territory where the work will occur.
Warning signs that need action
Stop and reassess if workers notice cracking, slumping, bulging or falling material; unexpected water; damaged shoring; movement near an adjacent structure; an unmarked service; changing ground conditions; exhaust or unusual odours; spoil or plant too close to the edge; unsafe access; or people entering an exclusion zone.
Controls should also be reviewed after rain, vibration, a change in excavation dimensions or method, a near miss, new work nearby or any indication that the existing system is not effective.
How Blue Safe can help
Blue Safe prepares and customises WHS documents for builders, subcontractors and trades. We can help develop excavation SWMS, risk assessments, permit forms, pre-start material and supporting site documentation around the actual scope, plant and work environment.
A document does not replace competent supervision, consultation, engineering input or effective controls on site, and no document can guarantee compliance. Blue Safe’s role is to help businesses put clear, practical and tailored documentation in place.
Official sources
- Safe Work Australia—Model Code of Practice: Excavation work
- SafeWork NSW—codes of practice
- WorkSafe Tasmania—Excavation Work Code of Practice
- NT WorkSafe—Excavation work Code of Practice
The national Model Code provides general orientation. It is not automatically applicable law in every Australian jurisdiction. Always check current local regulator guidance and requirements.