Primary Producers who register or renew their heavy vehicle (>4.5 tonnes) from 1 July 2018 up to 30 June 2020 will receive a rebate. The rebate covers some registration costs but does not include compulsory third party insurance, heavy vehicle inspection fees (if applicable), stamp duty (if applicable) and number plate fee (if applicable).

http://www.rms.nsw.gov.au/business-industry/heavy-vehicles/registration/drought-relief/pp-hv-refundsrebates.html

Primary producers may also be able to claim a refund on some past heavy vehicle registration charges paid from 1 July 2015 to 30 June 2018. Affected primary producers will be contacted by mail and notified of the process to claim their refund.