Criminal syndicates are using Australia’s “broken” visa system for human trafficking that is leading to the exploitation of foreign workers who are being paid as little as $4 an hour, an immigration roundtable in Canberra has heard.

Labor has called the meeting of migration and border security experts as it seeks to turn up the heat on the Coalition over its management of the visa system, pointing to the 80,000 people who have arrived by plane to claim asylum since 2014.

Only about 10% are found to be refugees, but the surge in claims means a backlog in processing that has left more than 200,000 people in the community on bridging visas who are vulnerable to exploitation.

The roundtable, convened by Labor’s home affairs shadow minister, Kristina Keneally, heard from John Coyne, the Australian Strategic Policy Institute’s head of border security, who warned the visa system was being exploited.

“Organised crime are indeed facilitating unlawful migration on a fee-for-service basis, using methodologies from fake identity documents, to gaming Australia’s visa system,” Coyne said

“Australia’s border security arrangements are being exploited, and individuals who have not been appropriately identified are at times entering the country.

“The Australian black economy is indeed being supported by organised crime, who along with businesses involved, are using these methods to exploit workers, and those involved are not paying taxes and are often remitting their salaries out of the country.”

Emma Germano, the horticulture president of the Victorian farmers federation, said that the Australian agriculture sector was at the “coalface” of the problem given the industry’s reliance on labour hire firms.

This meant growers feared being implicated in scams involving foreign workers, but were powerless to change the system. She said as many as 60% to 70% of workers on farms in some regions did not have proper work documents and were paid as little as $4 an hour.

“These poor workers who don’t have the law behind them will never come and work for us directly as growers. So as much as we might like to employ them directly, they’ve got a huge fear of retribution from these criminal syndicates who have often tricked them into coming into Australia, make them believe that they’ve got the right to work here when they get here, potentially taken their passports from them when they arrive,” Germano said.

“We’ve got growers who are paying upwards of $31 an hour for staff, and workers who are being paid as little as $4 or $8 an hour. That money is going somewhere in between. As a grower, I can assure you we would like for that money to be going into workers.”

Former deputy secretary of the department of immigration and border protection Abul Rizvi said the “eye watering” blowout in bridging visa numbers indicated a “sick system”.

He said that visitor visas now accounted for about 25% of the country’s total net overseas migration intake, in what was an “indication of a sick system”.

“In the past, 5%, perhaps 10%, may have been regarded as acceptable (but) 25 per cent is a problem. It’s flashing red,” Rizvi said.

“The people we’re talking about are generally vulnerable people. They will have little financial resources, and they are being exploited – they’re being exploited by criminals, and they’re being exploited by unscrupulous labour hire companies. They have a right to seek asylum, certainly, but they don’t deserve to be exploited.”

Keneally said the roundtable was aimed at bringing together “a coalition of organisations” who wanted to address the problem of plane arrivals, accusing the government of being “asleep at the wheel”.

“Let’s be clear that what we are talking about – we are talking about people smugglers moving their business model from boats to planes. That’s what’s happening here,” Keneally said.