(1) Subject to subregulation (2) , an authorised officer may use a portable weighing device for the purpose of determining the wheel load, single axle load, axle group load or aggregate axle load of a heavy vehicle.(2) A portable weighing device is not to be used for the purpose of regulation 6 if (a) the load to be measured in any single weighing operation is less than one tonne or more than 9 tonnes; or(b) the portable weighing device has not been (i) tested by the testing authority within the previous 6 months; and(ii) shown to have a limit of error less than 2%; or(c) any repairs to the mechanism have been carried out since the device was last tested and the device has not again been tested.(3) In this regulation testing authority means the Secretary of the responsible Department in relation to the Roads and Jetties Act 1935 or a person authorised by the Secretary to test portable weighing devices.