News Ltd reports that a "secret" ACTU report has found Labor's workplace changes breach international laws, which the paper says has contradicted the stance taken by the union's president Sharan Burrow.

The report was believed to have found the Fair Work Act replicated provisions of the former government's Work Choices laws and introduced elements that were unlikely to comply with Australia's international obligations, the Weekend Australian says.

Greens Senator Rachel Siewert told AAP she believed all along that the fair work bill was not compliant with the International Labour Organisation (ILO) convention.

"We tried to introduce a number of amendments to ensure it was compliant," she said.

]"The government didn't support that."

However, it was quite clear from this ACTU report that it wasn't the case, she said.

"We believe the government should move immediately to introduce amendments that ensure the fair work bill is in fact compliant.

"It's particularly important that they deal with the issue around builders and construction workers rights."

And that involved getting rid of the ABCC (Australian Building and Construction Commissioner), she said.

On media speculation the government won't commit to making any changes until the next election, Senator Siewert said, "We don't believe that they should be waiting that long."

She said the government went to the last election promising a fair set of industrial relations laws.

"That means ... they should be complaint with the International Labour Organisation's conventions," she said.

"Australia is a member of that and we believe they should be fixing their laws now, not waiting for some time in the future," she said.