The national livestock identification system for sheep and goats is now mandatory across the country.

The NLIS uses ear tags to identify the age and property of birth of sheep and goats born after January 1.

The Australian Livestock and Property Agents Association says the integrity of the system will be compromised, because each state is introducing exemptions to keep producers happy, and that will damage traceability.

President of the Sheepmeat Council of Australia, Ian Feldtmann, says the new system will ensure livestock can be traced adequately.