There are number of work visa classes. Some are for short stays. This page deals with 457 visas which are employer-sponsored and lets people from overseas stay here for up to four years.
Work visas are a good way for a country to cope with a boom, especially if that boom is confined to a particular sector (like mining a few years ago). The workforce can be quickly expanded and when the boom is over, the people go home.
But it's a problem if there is no particular shortage in an industry, yet employers still sponsor people on 457 visas. Before allowing an employer to sponsor 457 visas we should verify that the employer
457 applications should be handled by a group that operates a little bit differently to how immigration officials normally operate. That group would not only process the application but also have the capability to refer job seekers to the applying employer.