Under Section 41 of the Motor Vehicles Act, misuse of Primary Producer Registration is not allowed.

But........ under the Regulations there are some local fundraising circumstances that provide an exemption to Section 41 of the Act

Primary producer registered vehicles are allowed to cart produce for local fundraising events under the following circumstances in Regulation 79:

(a) the purpose for which the vehicle is used is solely the carrying of primary produce to assist a charitable organisation or a sporting organisation in fundraising activities; 
and 
(b) neither the owner of the vehicle nor a person using the vehicle (if not the owner) receives a monetary or other material benefit (including out of pocket expenses relating to the use of the vehicle) in relation to that use of the vehicle;
and 
(c) the use of the vehicle is within an area having a radius of 75 kilometres from the garage address of the vehicle.