Geotechnical Engineering Services

Auckland | Hamilton | Nelson | New Plymouth

HD Geo provides geotechnical engineering services for residential, commercial, infrastructure and network projects across New Zealand. 

Our team includes Chartered Professional Engineers (CPEng), Engineering Geologists and NZTA-accredited practitioners. We work on projects of all sizes — from small residential sites needing a geotechnical report for building consent, to large infrastructure projects with complex ground conditions and staged construction. 

Our Geotechnical Service Includes:

Ground Investigation & Site Assessment: We assess subsurface soil and rock conditions using trial pits, Cone Penetrometer Testing (CPT) testing, borehole drilling, and dynamic cone penetrometer (DCP) testing.

Our investigations are supported by engineering geological and geomorphic mapping, rope‑access inspections, and hazard identification. We also use drones where appropriate to provide additional insight into site conditions and landform features. Early, well‑targeted investigation helps reduce geotechnical risk and avoid unnecessary cost during design and construction.

Slope Stability Analysis: We assess the stability of existing slopes and proposed earthworks using industry‑standard modelling software, relevant guidelines, and regulatory requirements to support safe, buildable designs.

Foundation Design: We assess whether standard NZS 3604 foundations are suitable, or design shallow and deep foundations where required, including pile foundations, raft foundations, and ground improvement solutions tailored to site‑specific conditions.

Retaining Wall Design: We design gravity walls, cantilevered walls, anchored walls and reinforced soil walls. All designs comply with NZ standards and account for seismic loading.

Rockfall design: We design passive rockfall mitigation systems, including catch bunds, fences, and attenuators. Where space is constrained or any level of rockfall risk is unacceptable, we also design active systems such as rock anchors and mesh to stabilise rock at source.

Seismic & Liquefaction Assessment: We evaluate seismic hazard and liquefaction risk for buildings and infrastructure in accordance with current NZ standards and guidelines.

We are qualified:

  • Chartered Professional Engineer (CPEng)

  • Professional Engineering Geologist (PEngGeol)

  • NZTA ARL accreditation

  • NZTA Road Inspectors Certificate.

  • CAA Part 102 certified for Drones

These credentials mean your reports, designs and certifications are accepted by Councils, NZTA, stakeholders and regulatory authorities’.. 

Geohazard Assessments: We map landslide and rockfall hazards, undertake engineering geological assessments, and assess risk for development sites, infrastructure corridors, and walking tracks. Our assessments are informed by recognised risk frameworks, including AGS (2007), Natural Hazard Risk Assessment (NHRA), and Assessed Risk Level (ARL) methodologies. 

Prepurchase due diligence: Before you buy, subdivide, or invest, we can help you understand geotechnical risks early. Our pre‑purchase assessments combine desktop review and a site walkover to identify key constraints and development considerations before you commit.

Construction Monitoring & PS4 Certification: We provide construction observation and compaction testing, and issue Statements of Professional Opinion in accordance with NZS 4431 for large‑scale earthworks. We also provide PS4 geotechnical certification for building platforms, Building Location Areas (BLA), and minor earthworks to support building consent applications.

Geotechnical Peer Review (PS2): We provide independent geotechnical peer review of designs and reports for councils, developers and project teams. 

Temporary Works: We design sheet piling, temporary slopes and piling or machinery platforms to facilitated construction.

Expert witness: We provide expert witness services for hearings and mediation, offering clear, independent geotechnical and engineering geological evidence grounded in experience and sound technical judgement.

Additional services: Site conditions can be complex, and not every project fits neatly into a standard service offering. If you require geotechnical support that isn’t described above, feel free to get in touch and we can discuss your requirements.

Need a geotechnical engineer for your project?

Talk to the HD Geo team today to discuss your requirements or request a quote.

Call 0800 080 088 or email queries@hdgeo.co.nz, and one of our geotechnical engineers will be happy to help. With offices in Auckland, Hamilton, and New Plymouth, we support projects across New Zealand.