This page belongs to: National Measurement Institute

Verifying measuring instruments for trade

Servicing licensees and their nominated verifiers test and verify measuring instruments used for trade.

Utility (electricity, water and gas) meters must be verified by a utility meter verifier.

When verifying an instrument:

  • confirm the instrument is pattern approved
  • use appropriate equipment and reference standards
  • test the instrument using the relevant national instrument test procedures and any test specified in the certificate of approval 
  • confirm the instrument operates within the appropriate limits of error
  • apply a verification mark if the instrument meets these requirements
  • complete and submit verification form and test report (for complex instruments).

Find specific information about:

Submit these forms along with any test reports to

Read the licensees guide to completion of Form 6 and Form 6A to find out more.

To be accepted by our automated system, you need to complete these form correctly.

You must:

  • only use the tab key to move across the cells, not the space bar
  • enter the full details in each cell and not input ‘as above’ 
  • send test reports and verification forms together in the same email
  • only provide the licensee and verification mark, not the year and month
  • never change the format, including merging, adding, deleting or renaming cells, rows or columns 
  • only enter one NMI number for each cell
  • use the number 0 (zero) and not the letter ‘O’ for your verifier number.

Test reports

When you verify a complex measuring instrument you must complete and submit a test report and verification form to the NMI.

You will need to do this for:

  • bulk flow metering systems for petroleum products, non-petroleum products, LPG and LPG dispensers (subclasses 5.2, 5.3, 10.1 and 10.2)
  • weighing instruments exceeding 3 t capacity (subclass 6.4)
  • belt weighers (subclass 6.5)
  • automatic rail weighbridges (subclass 6.6) 
  • wheeled loaders (subclass 6.8)
  • totalising hoppers (subclass 6.9).

Any measuring instruments verified under the above licence sub-classes must have a test report submitted with the Form 6 to NMI by e-mailing within 14 days from the date of instrument verification.

Sealing measuring instruments

The certificate of approval will state if you will need to seal a measuring instrument after verifying it. All seals must be tamper evident.

Physical seals can include:

  • lead plugs
  • sealing wires with crimp seal (lead or plastic) 
  • adhesive label or foil.

An electronic seal could be an access counter.

You should only put your servicing licensee mark (three upper-case letters) on the seal.

Some measuring instruments have multiple sealing points. If you break one of the seals to make a repair, then only that point needs to be resealed and marked with your servicing licensee mark.

Do not use NMI-supplied verification labels as a seal. Seals should not be able to be confused with a verification mark.

Verification marks

You can place a verification mark on:

  • a label that will be affixed to the instrument
  • a stamp plug secured to the instrument
  • the surface of the instrument.

Additionally, you should place a verification mark in a location:

  • easily accessible to a servicing licensee or a trade measurement inspector
  • unlikely to be damaged
  • where it will stay affixed, clean and legible.

You only mark an instrument with one verification mark. 


Verification marks must be permanent. The best option is to use a stamping tool on labels. 

If you use pens or permanent markers, you can cover over the label with clear contact to prevent the mark from being wiped off during regular cleaning.

You must permanently attach labels to the instrument. The label should not be:

  • used as both a seal and a verification mark
  • folded over 
  • affixed to cases and walls adjacent to instruments.

If possible, place verification marks and labels where consumers can see them.

Stamp plugs 

If you use stamped plugs, there may be insufficient space for a full nine-character mark. Contact us on 1300 686 664 and select option 2 or for how to comply with the regulations. 


A verification mark consists of nine alphanumeric characters made up of: 

  • a servicing licensee mark of three upper-case letters
  • an authorised verifier code of four numbers (from the last four digits of the verifier’s registration number, e.g. the code for VR-00234 is 0234)
  • a month and year code: an upper-case letter for the month and a single digit for the year when you verified the measuring instrument.

Month codes 

  • A: January 
  • B: February
  • C: March 
  • D: April
  • E: May
  • F: June
  • G: July
  • H: August
  • I: September 
  • J: October 
  • K: November 
  • L: December

Year codes

  • 9: 2019
  • 0: 2020
  • 1: 2021
  • 2: 2022
  • 3: 2023
  • 4: 2024
  • 5: 2025
  • 6: 2026
  • 7: 2027
  • 8: 2028

In the example ABC0234K2:

  • ABC is the servicing licensee’s mark
  • 0234 are the last four digits of the verifier’s registration number (VR-00234)
  • K2 is the date of verification (November 2022).

Was this page helpful?

Was this page useful?

Thank you for your feedback!

Would you like to tell us more about your experiences with this page? (optional)

Feedback you provide will not be directly answered. If you require a reply, please reach out to the page contact directly. For any other queries, please use our general enquiries web form.

Please do not include personal or financial information (e.g. email addresses, phone numbers or credit card details).

Your feedback is covered by our privacy policy.