The Turnbull Government has ended the 457 visa, and split some of the jobs it used to cover into two separate visas.
One list is meant to be for higher skilled jobs, mostly in medicine and engineering.
Those migrant workers can still get four-year visas, and can then apply to stay in Australia permanently.
But the other list, which contains most of the jobs previously under the 457, can only stay for two years.
Immigration minister Peter Dutton says those workers will never get to settle in Australia.
"We now with the short term skills visa, we don't have a permanent pathway, for those people applying under that new arrangement. That is a big change it's not an as of right that you'll become a permanent resident and an Australian citizen."
The CEO of the Migration Council, Carla Wilshire, says closing the pathway to permanent residency for so many workers creates a two-tier system.
"One of the concerns is that this will break up our temporary migration program into two different tiers: one that has an option for permanent residency and one that doesn't. And the one that doesnt might end up looking a lot more like a guest worker system in Australia, rather than an option for permanent residency. And that has really big implications for the types of migrants that come here and for the incentives in terms of staying in Australia."
Ms Wilshire says many migrant workers who come to Australian on 457s are motivated by the propect of one day gaining permanent residency.
She says removing that incentive will make it harder for businesses to convince workers to make the journey.
"One of the things that the Australian migration program really relies on is being able to attract the best and the brightest in all different skills categories, across all different positions, all different sectors of the economy. What we need to be able to do is to provide really strong incentives to get the best and the brightest, and permanent residency in Australia is a really big part of that."
The majority of IT jobs have been moved to the two-year visa, with no prospect of permanent residency.
Nick Ingall is from tech company Safety Culture.
"It's already a very competitive market as is, so having the ability to top up our workforce with individuals from abroad is key to us being a successful business."
One of his staff is Ben Morrison, a 31 year-old American who moved from Silicon Valley to work in Australia on a 457 visa.
Workers already here on 457s won't be affected by the change.
But Mr Morrison says he might not have come, if the possiblility of a life in Australia wasn't on the table.
"What attracted to the 457 was the ability to actually stay. to come to Australia and stay. It's a place that I've always wanted to visit when I was a kid and it kind of stuck with me, and the fact that I have an occupation that allows me to come to another country that I want to be in and visit, and possibly stay indefinitely, is a pretty amazing opportunity. "
But not everyone in the IT industry thinks there is a problem with incentives.
CEO of the Australian Computer Society, Andrew Johnson, says most 457s working in the sector work for multinationals, and don't expect permanent residency.
"I think the bulk - you know, anecdotally - the bulk of people participating on 457s in technology-related areas would be in the multinational-type space and they're filling a gap that's an immediate need. So I couldn't come up with a number as to how many would be not incentivised to pursue that, but we have other migration pathways for permanent residency."
The government is reportedly planning a broader overhaul of immigration.
The Prime Minister is expected to announce major citizenship changes, including limits to the number of times people can fail the citizenship test.>
