A quarter of Australia's vegetable growers are forced to abandon valuable produce which is left to rot because they can't find enough workers to pick and pack it, a new report has found.
The study's project leader, Associate Professor Joanna Howe, from the University of Adelaide Law School, said the challenge in finding labour had become unsustainable and the amount of waste was a significant loss to the Australian economy.
"We are seen as the food bowl of Asia, but if we don't have the workers to get the produce out from the farms and into the supermarkets and out for export, it is a real concern about the sustainability of that industry," she said.
"It means that growers are finding it hard to expand because they are not sure they have enough workers to meet that expansion.
"We do not have a sustainable way at present of meeting labour supply in this industry."
The new study by researchers from the University of Adelaide and University of Sydney, to be released this week, calls for major reform to working holiday maker and Pacific seasonal worker visa programs to address labour supply challenges and exploitation of vulnerable workers.
Australia's vegetable industry is unique internationally in its heavy reliance on working holiday makers as its main source of low-skilled labour.
"Experience abroad suggests that dedicated labour migration pathways for low-skilled horticultural workers are preferable to relying on generic, dedicated low-skilled, multi-industry work visa pathways or de facto low-skilled work visa pathways like that provided under the working holiday maker program," the report says.
The report by Dr Howe and Professor Alex Reilly from the University of Adelaide Law School and Associate Professor Diane van den Broek and Dr Chris F. Wright from the University of Sydney Business School says the reliance on the working holiday maker visa workers is preventing Australia's vegetable growing industry from developing a more secure and sustainable labour supply and expanding business.
The study surveyed 332 vegetable growers across Australia and found two thirds had difficulty getting low-skilled workers to pick, pack and grade their produce.
Of those who had difficulty recruiting labour, 63 per cent left vegetables unpicked. This group represented a quarter of the growers surveyed.
Dr Howe said about 40,000 backpackers extended their working holiday maker visa for an extra 88 days.
"But we know that the visa extension is heavily linked to visa exploitation and we have heard from many growers that those workers often only stay 88 days, aren't productive and aren't committed to staying in the sector beyond the 88 days," she said.
"It is highly concerning that an industry that is of such critical importance to our GDP and our food security and export markets is so reliant on this transient labour force.
"Local workers don't want to do this work in great numbers anymore - it is low status, low paid and difficult conditions and often very short-term casual work that doesn't give them any security."
The temporary visa pathway meant backpackers could only stay for 88 days to work as fruit or vegetable pickers and packers.
The study found that many growers perceived the seasonal workers program as dogged with lengthy bureaucratic delays and only allowed workers from a limited number of countries to stay in Australia for six to nine months.
"A more long-term solution, if we really want to future proof labour supply, is to reform the Pacific seasonal workers program and to expand it beyond the Pacific to other countries in south-east Asia such as Indonesia, Taiwan and South Korea," Dr Howe said.
"These countries have strong horticultural backgrounds and there are lots of workers that want to come from those countries and so if we expand the source countries, expand the numbers and reduce the bureaucracy with our program then we can finally have a sustainable solution for the horticulture industry.
"It is a special industry that needs a dedicated visa for it. The current solutions just don't work."
The angry reaction of farmers to the federal government's decision last year to increase the backpacker tax reflected the fragility of their labour supply.
"The research has identified a serious endemic labour supply challenge and it is only going to get worse because locals are removing themselves from this industry and the current visa options do not provide a holistic and comprehensive response," Dr Howe said.
Dr Wright said the report highlights the importance of horticulture to the Australian economy, and the considerable growth in demand for Australian produce in export markets.
"Part of addressing this challenge of labour supply is ensuring that workers in the industry are treated fairly and in accordance with the law," he said.
"Instances of workers being paid below the award or mistreated is bad for these workers involved, it's bad for the reputation of the industry, and it undermines the competitiveness of legally compliant growers."
Dr Wright said the study found 80 per cent of growers who have difficulty getting workers pay award hourly rates or higher.
"Of those growers who never have recruitment difficulties, 67 per cent claim to pay the award or higher, compared to 19 per cent who pay below the award," he said.
"These figures indicate that growers who comply with their legal obligations and who provide better management/employment practices are more likely to have difficulty finding workers than those who admit they do not comply with their legal obligations.
"This finding confounds the conventional expectation that employers offering higher wages and better working conditions will find it easier to attract and retain workers."