Before a Contractor start work of risk with us, we want to know they are a safe company who has good systems, capability, and backed with credible evidence. Prequal is one of the first steps for selecting good Contractors.

We use Prequal NZ, an assessment subsidiary of Impac, to give us an assessment report with a % score of a contractor. Prequal NZ is widely used by NZ's largest companies, and a Contractor can simply supply their prequalification to other companies they do business with. Prequalifying safe and good Contractors are major steps of the Principal's Guide to Contracting to meet Health and Safety Legislation.

All Contractors who do physical work / high risk work for us must be prequalified and meet a minimum required score of 60%. If a Contractor scores between 60% and 80%, additional controls must be put in place to ensure Contractors have the support they need to work safely.

It can take some time for both Contractor’s and Prequal NZ to work through the requirements. New Contractors should give their safety evidence to Prequal NZ about 3 months before a tender closure date. It takes Prequal NZ around 2 months to assess their evidence. See their FAQs.


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Prequal Renewal Times

Contractors need to renew every 6 to 24 months depending on their score. The re-submission criteria is exactly the same as the first time. So it pays to have good safety and get a high score early on.

0 to 30% need to renew within 6 months

30 to 60% need to renew every 12 months

60 to 100% need to renew every 2 years

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  1. We inform prospective contractors of our H&S requirements in our communications and tender documents
  2. We inform Prequal NZ that there is a non-prequalified yet prospective contractor
  3. Prequal NZ does the 'leg work' and guides the contractor in the assessment process
  4. The contractor provides their H&S evidence and information to Prequal NZ to assess
  5. Prequal NZ assesses the contractor
  6. Prequal NZ gives a score of the contractor, and provides Wellington Water the score too
  7. We use this prequalification score together with other scoring attributes (e.g. pricing, past performance) in the contractor's tender