Numbers in Australia's expanded labour mobility scheme have grown by 450 percent in the past five years.
In June 2019, there were just under 6000 Pacific Australian Labour Mobility (PALM) scheme visa holders in Australia and as of May this year there are over 32,000.
The Development Policy Centre at the Australian National University said "rapid growth" of the scheme has resulted in "a big shake-up".
It puts this down to several factors, including the preference given to PALM workers during the Covid pandemic and the expansion of the scheme from only seasonal to multi-year work.
The Centre also points to very high growth by some of the countries supplying the workers.
According to data from the Department of Home Affairs, Fiji has become the biggest supplier, now up to 6,379 after being at just 266 in 2019.
Vanuatu is close behind at 6217 but it was at 2215 in 2019.
There are also significant numbers from Solomon Islands, Tonga and Timor Leste.
"The massive growth over the last five years has undermined the benefit gained from being a first-mover, and given other countries a second chance. Negative publicity around PALM in some of the early big senders, especially Samoa and Vanuatu, has encouraged employers to look elsewhere," Devpolicy's Richard Cain and Stephen Howes wrote.
"And the introduction of entirely new industries into PALM has reduced the advantage that early movers had in horticulture via their experienced return workers."