But while cooking up lunch in a St Kilda hostel, the two friends have found themselves among a dwindling number of Irish backpackers who were willing to make the long trip to Australia.

"When I was a teen, every second week there was an Australia-leaving party," Mr Keenan, 25, said.

"It has slowed down. Now you get maybe one every two months."

Mr Keenan said many of his friends back home are now considering other options, such as a working holiday in Canada, with its proximity to the US, shorter flight from Ireland and football-friendly time zone.

Young people are also starting to choose to stay in Ireland rather than travel as the economy picks up, he said.

The trend among the Irish, however, has become a major concern for Australia's tourism operators and farmers, who rely on backpackers to work in cafes, pubs and in fruit picking.

The number of working holidaymakers from Ireland has dropped by more than half in only three years, immigration department figures show.

There were nearly 12,000 working holidaymakers from Ireland given 417 visas in 2012-13, but that number dropped by 56 per cent to just over 5000 people last financial year.

There were similar double-digit declines seen in backpackers coming from Taiwan and South Korea over the same period.

The total number of working holiday visas granted each year fell by 5.3 per cent to 226,812 people last year, the figures reveal.

Meanwhile, the hospitality industry is suffering a shortage of 38,000 workers, which could grow to 120,000 within four years, according to a recent Deloitte Access Economics report.

Richard Mulcahy, CEO of industry body AUSVEG, said far more needs to be done to entice backpackers to come here.

"We are facing a very real threat to the future of our industry," he said.

"The working holidaymaker program, and especially the second-year visa extension for regional work, is a huge contributor to the on-going productivity and profitability of the Australian vegetable industry."

He said concerns over labour hire firms, which led to a sweeping government inquiry in Victoria, could also be deterring backpackers from working on farms. The lower Australian dollar could be a factor too, he said.

Both Mr Keenan and Mr Jamieson worked on Queensland farms to get a one-year extension on their visas, but didn't enjoy the experience.

"It was kind of like slave labour, to be honest," said Mr Jamieson, 24.

Backpackers have also complained about being underpaid while others have been injured on the job, as seen in November when an Irish backpacker suffered a severe head injury while working at a fruit packing plant in Shepparton.

Deputy manager at Melbourne Central YHA, Michael Locke, said some backpackers talked about having bad experiences with farm work, but it remained popular for those wanting the longer visa.

"In speaking to a lot of backpackers, they do like to do fruit picking because then they get that extra few months on their visa and they can stay in Australia a little bit longer," Mr Locke said.

 Tourism and Transport Forum CEO Margy Osmond said the cost of a working holiday visa – now at $440 – deters backpackers from coming here, as will ending the $18,000 tax-free threshold, beginning July 1.

"Providing affordable visa options for backpackers who want to work on their holidays is the first step to reversing the decline in the number of visas being issued," she said.

Tourism Minister Richard Colbeck said the government has expanded the working holidaymaker program to include a handful of new countries, including China.

"We recognise the importance of this market sector," he said. "We will continue to work on and monitor this program."