FARMERS have lashed out at the "crackdown'' on skilled-worker visas

Immigration Minister Brendan O'Connor last week said 457 visas would be tightened to ensure they were only used to address genuine skills shortages, giving Australian workers a "fair go''.

Under the changes, employers will be required to prove they are filling a position for which there is a genuine shortage of workers.

"It has become clear . . . that the growth in the 457 program is out of step with those skills shortages, and the government has evidence that some employers - and I emphasise that word, some - are using 457 visas to discriminate against locals,'' Mr O'Connor said.

"This cannot continue.''

Victorian Farmers Federation workplace relations committee chair Meg Parkinson said the changes would cause major problems for farming, especially the pig and dairy industries.

"Farmers turn to people on 457 visas because they can't find locals to fill the jobs,'' she said.

"They will simply go out of business if they can't find labour.''

Ms Parkinson said there had been no consultation with the agriculture industry before the changes to the visa were announced.