Agricultural contractors fear maize, sileage and other crops might go unharvested because of bureaucratic delays in Wellington.
They say people who drive complex machinery like combine harvesters are stuck in immigration queues overseas, despite having been approved for entry to New Zealand almost a month ago.
Only a few of the 210 approved by the Government have come in, and Rural Contractors New Zealand says this puts many operations as risk.
Its chief executive Roger Parton has written letters of protest to Kris Faafoi and Damien O'Connor, who still formally hold ministerial warrants at this stage for immigration and primary industries.
Parton says many of the would-be workers are skilled operators with years of experience who work the northern harvests during the northern summer and then come to countries like New Zealand for the southern summer.
The 210 machinery drivers were approved along with 30 vets and 570 deep sea fishing crew.