Backpackers are an "absolutely critical" flow of labour for the farm sector, according to National Farmers' Federation president David Jochinke, Murra Warra.
Mr Jochinke warned the government must continue to ensure there was a requirement for those backpackers travelling to Australia to complete their 88 days of regional work.
From July 1, visa requirements change for British backpackers which mean they would not be required to complete a stint working regionally to gain their second year's visa.
"We've had a survey done to indicate that changing that requirement for that workforce to spend 88 days in regional areas will bring a lot of industries to their knees," Mr Jochinke said.
"Quite simply, there is no other mechanism to have that seasonal, casual, workforce that can move around between farms."
He said farmers were warning they would change what they grow or even walk away from farming altogether if their access to overseas workers was reduced.
Mr Jochinke highlighted a survey completed by the NFF which showed that 35 per cent of farmers felt the visa requirement change would have a "catastrophic impact".
Almost 34% of the workforce of the farmers surveyed were backpackers.
The NFF said farmers were also abandoning the Pacific Australia Labour Mobility (PALM) scheme.
Mr Jochinke said the scheme appeared to be "faltering" with data from the Department of Employment and Work Relations showing an 11pc fall in the number of PALM workers employed in agriculture in the six months to January.
"With the Government piling on red tape to access the PALM Scheme, farmers are turning to other sources for workers, making backpackers an even more critical part of the agricultural workforce than ever before," he said.
"Alarmingly, farmers are warning if access to backpackers is eroded further it will mean increases in food prices, a fatiguing workforce and, in the worst case, farmers walking away from the industry.
"More than half of farmers surveyed said they would consider switching commodities or leaving the industry altogether if access to workers was reduced."