The Federal Government has suspended private companies from entering Comcare, the federal workers' compensation vehicle set up in 1988 for Commonwealth public servants.

A moratorium on new entries took effect on December 11.

In the past few years the scheme has admitted thousands of private sector employees under criteria that the ALP in the run-up to the election pledged to review.

Unions say firms can escape their obligations by opting out of state compensation arrangements and joining Comcare.

The states, which all have Labor governments, are being encouraged to find ways to bring cross-border consistency to their workers' comp legislation. National companies have long complained at the cost of complying with different state laws.

The Victorian Government has already begun a review targeting complex aspects of its compensation legislation.