Unions have lodged an urgent hearing with FairWork Australia, as anger mounts over a Fairfax decision to cut 19-hundred jobs.

The media company will close printing presses in Sydney and Melbourne and downsize two major mainland papers as it focuses on web content.

The move won't directly affect the company's regional Tasmanian papers, although the media union's Tasmanian organiser Luke Crowley says there are concerns about the offshoring of subeditors.