The Construction Forestry Mining and Energy Union is concerned about the impact that might have on local jobs amid high unemployment and wants tougher rules for 457 temporary worker visas.
NINE NEWS, 7 May 2014
New government figures show there were almost 111,800 people on 457 visas in Australia at the end of March.
That's more than ever before, although it's only about 1500 more than six months earlier.
CFMEU national secretary Michael O'Connor said the six per cent rise in the past year was much faster than the growth in employment generally.
The immigration department report says there were a third fewer applications for visas in the March quarter than the previous year.
The number granted also dropped, by 23 per cent.
Last June, the previous Labor government cracked down on use of the visas, requiring many prospective employers to prove they searched for Australian workers before looking overseas.
More recently, an Abbott government bid to remove red tape has reportedly led to a loophole allowing bosses to hire an unlimited number of foreign workers.
Mr O'Connor wants the rules tightened further.
He'd like employers in all industries to have to show they looked to hire locally before applying for the visas.