Queensland Vehicle Modification Guide
Engineering, certification and approval pathways for modified light and heavy vehicles in Queensland.
KME Vehicle Engineering helps vehicle owners, workshops and businesses understand the engineering and approval pathway for vehicle modifications in Queensland.
Reviewed by Daly Kelly — KME Vehicle Engineering
Last reviewed: September 2026
How the vehicle modification process works in Queensland
Vehicle modification approval in Queensland depends on whether the vehicle is a light vehicle of 4.5 tonnes GVM or less, or a heavy vehicle over 4.5 tonnes GVM.
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Light vehicle modifications are administered through the Queensland Department of Transport and Main Roads (TMR), including the Queensland Approved Person Scheme. Heavy vehicle modifications are regulated through the Heavy Vehicle National Law framework and the National Heavy Vehicle Regulator (NHVR). Department of Transport and Main Roads
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The technical and certification pathway depends on the modification. Some minor changes may not require formal approval, while common or complex modifications can require certification by an appropriately authorised person or prior regulator approval.
1. Determine the pathway
Confirm whether the vehicle falls under the Queensland light vehicle or heavy vehicle modification framework.
2. Complete the engineering
Undertake the assessment, calculations, supporting evidence, modification work and inspection required for the project.
3. Complete the QLD approval process
Obtain the required certification, modification documentation and regulator approval for the vehicle.
Light or heavy vehicle?
In Queensland, the 4.5 tonne GVM threshold matters. TMR's vehicle modification guidance applies to vehicles up to 4.5 tonnes GVM, while the NHVR regulates modifications to vehicles over 4.5 tonnes GVM. Department of Transport and Main Roads
Light vehicle modifications in Queensland
Vehicles up to 4.5 tonnes GVM
Queensland TMR administers modification approval for light vehicles with a GVM of 4.5 tonnes or less.
Depending on the modification, the pathway may involve no formal approval, inspection against an approved code, certification by a Queensland Approved Person, or direct approval from TMR where no approved modification code applies.
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Minor modifications generally do not require formal approval.
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Complex modifications must comply with a Queensland-approved modification code.
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Complex modifications require inspection and certification by an appropriately authorised Approved Person.
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Modifications outside the approved codes may require direct TMR approval. Department of Transport and Main Roads
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Heavy vehicle modifications Queensland
Vehicles over 4.5 tonne GVM
Heavy vehicle modifications are regulated under the Heavy Vehicle National Law and NHVR framework.
VSB 6 is the primary national technical standard used by Approved Vehicle Examiners for many common heavy vehicle modifications.
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Common modifications within the NHVR Code may be approved by an Approved Vehicle Examiner (AVE).
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VSB 6 sets the technical requirements for many common heavy vehicle modifications.
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Modifications outside the NHVR Code require approval from the NHVR before the modification is certified.
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Where an approved VSB 6 modification passes inspection, the AVE issues the modification certification and modification plate.
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Queensland Approved Person/Approved vehicle examiner
Daly Kelly of KME Vehicle Engineering is a Queensland Approved Person, authorised across a broad range of light and heavy vehicle modification codes.
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This enables KME Vehicle Engineering to assess and certify applicable Queensland vehicle modifications within Daly's authorised modification-code scope.
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The required pathway still depends on the vehicle, modification and applicable Queensland or NHVR requirements.
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Who certifies vehicle modifications in Queensland?
The person who can certify a modification depends on the vehicle category, modification and applicable modification code.
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Light vehicles — Queensland Approved Persons
For light vehicles up to 4.5 tonnes GVM, complex modifications covered by a Queensland-approved modification code must be inspected and certified by an Approved Person authorised for the relevant modification code.
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If the modification complies, the Approved Person can issue a Certificate of Modification and fit the required modification plate. Modifications for which no Queensland-approved code exists may require direct TMR approval.
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Heavy vehicles — Approved Vehicle Examiners
For heavy vehicles over 4.5 tonnes GVM, VSB 6 is the primary standard used by Approved Vehicle Examiners (AVEs) to approve many common heavy vehicle modifications under the NHVR framework.
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The examiner must hold the appropriate approval for the modification being certified; more complex modifications can require an approved design or prior NHVR approval.
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Interstate modifications and Queensland registration
A modification certificate or approval issued in another state or territory is not automatically accepted for a Queensland-registered light vehicle. If a modified light vehicle is being registered or transferred into Queensland, TMR may require the modification to be assessed against Queensland requirements and certified by a Queensland Approved Person for the relevant modification code.
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Heavy vehicles are different. Where a heavy vehicle modification has been approved under the Heavy Vehicle National Law framework using the applicable NHVR/VSB 6 pathway, that approval may be recognised across participating HVNL jurisdictions, subject to the relevant registration and modification requirements.
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Interstate approval does not always mean Queensland acceptance.
The correct pathway depends on the vehicle category, the modification, where it was originally certified and how the vehicle will be registered in Queensland.
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GVM upgrades in Queensland
A GVM upgrade increases the maximum permitted Gross Vehicle Mass of a vehicle.
In Queensland, the approval pathway depends on whether the vehicle is a light vehicle or heavy vehicle, whether the upgrade is pre-registration or post-registration, and whether an approved modification code or heavy vehicle modification pathway applies.
The engineering assessment can consider axle ratings, suspension, braking, wheels and tyres, available technical evidence and the proposed target GVM.
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Light vehicles
Post-registration GVM upgrades for vehicles up to 4.5 tonnes GVM generally sit within the Queensland light vehicle modification and Approved Person framework, subject to the applicable code and vehicle-specific requirements.
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Heavy vehicles
For vehicles over 4.5 tonnes GVM, GVM re-rating and related modifications are assessed through the applicable VSB 6 / NHVR heavy vehicle modification pathway.
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A GVM increase does not automatically increase GCM or towing capacity.