Legislation cracking down on what Labor has described as "widespread rorting" of the 457 foreign worker visa scheme looks to be on shaky ground, with a key independent unlikely to support it.

Rob Oakeshott says he remains unconvinced the legislation is necessary and is unlikely to vote for it.

"I'd be leaning towards no, and the Government knows that," he said.

"As yet the rhetoric of widescale rorting of 457 visas does not look to be matched by any reality of actual problems, if they can prove that up, please provide it. But to date they haven't."

Immigration Minister Brendan O'Connor says the legislation is justified.

"I think there is compelling evidence, and all members and senators can make their own decision on that. Mr Oakeshott will be provided any information he seeks from us in relation to that."

The Coalition is opposing the legislation.