The federal opposition in Australia wants a parliamentary inquiry into a proposed government crackdown on 457s, the temporary skilled migrant visa programme.
Coalition immigration spokesman Scott Morrison said the government has not properly consulted with industry on the changes or provided a regulatory impact statement.
"They are looking to ram through what is nothing less than an attack on skilled migrants," he told reporters.
AAP reports the coalition will not support the legislation.
Mr Morrison said Labor was doing the bidding of the unions.
Immigration Minister Brendan O'Connor is under fire for claiming there is widespread rorting of the visa scheme - a claim employers reject as baseless.
AAP reports Labor's proposed changes will require companies to make every effort to employ Australians before resorting to foreign workers.
An employment watchdog agency will be given increased powers to monitor the visa scheme, with a 10-fold increase in the number of compliance inspectors.
Mr O'Connor insisted the government had evidence the scheme was being rorted.
"I'm a little tired of being told we don't have evidence," he told ABC Radio, adding there had been a spike in 457 visas.
"The problem is the group think amongst journalists is quite remarkable in this area."