Federal Opposition Leader Bill Shorten says he has reached a compromise with the Government and will now support the Chinese Free Trade Agreement.

"Labor now has achieved what we believe to be satisfactory legal protections," Mr Shorten said.

It comes after an expensive union campaign against the deal and several Labor MPs saying they could not back it.

The Opposition had wanted amendments to the Migration Act but has instead settled for changes to regulation.

It said it had won concessions around labour market testing and ensured Chinese workers would need to have the right skills to work safely on Australian construction sites.

Labor had proposed lifting the base amount foreign workers on 457 visas were paid from $53,900 to $57,000.

Instead, the Opposition said it had secured a change which would see a foreign worker's wages benchmarked against the amount local workers are paid if they were part of an enterprise agreement rather than the award rate, which is often lower.

"For example in the Pilbara and the like, you would have a different rate obviously in that location than you might have in different parts of urban Australia," Labor's trade spokeswoman Penny Wong said.

"So that is an additional protection for Australian wages and conditions."

"The economic proposition being the economic incentive to bring someone in on a lower rate of pay than you would have to pay an Australian worker is removed."

Trade Minister Andrew Robb said he was pleased there was now bipartisan support and had moved to assure China that the deal itself remained unchanged.

"The agreement we've reached with the Opposition will in no way contravene the commitments that have been made in the FTA and it in no way discriminates against our major trading partner," he said.

The Opposition held a special Caucus meeting this morning to discuss the issue.

The Caucus debate was described as "robust".

Labor MPs Kelvin Thomson, Melissa Parke and Doug Cameron spoke against the deal, while Richard Marles, Matt Thistlethwaite and Jim Chalmers spoke for it.

The Greens say Labor has caved in to the Coalition at the expense of Australian workers.

“Whilst the Labor and Liberal parties will be slapping each other on the back and celebrating this as a political victory for themselves, many Australian workers are likely to feel this is anything but a victory," said Greens Trade spokesperson Senator Peter Whish-Wilson.

“These trade deals are a Trojan horse for Labor market deregulation agendas, and giving special rights to corporations to sue over democratic government decisions."