ABC chairman Jim Spigelman has strongly criticised the federal government's proposed anti-discrimination law, saying it poses risks to freedom of speech.

Mr Spigelman, former New South Wales chief justice, said there was no justification for including the notion of ''offending'' in the definition of discrimination.

The legislation consolidates several anti-discrimination laws, including that on racial discrimination, which refers to treatment that offends. The proposed law extends ''offending'' into the definition of discrimination for all purposes.

Delivering an oration on Human Rights Day, Mr Spigelman pointed out that none of the other existing Commonwealth acts - covering sex, disability and age discrimination - included conduct that only offended.

The freedom to offend was an integral component of freedom of speech. ''There is no right not to be offended. I am not aware of any international human rights instrument, or national anti-discrimination statute in another liberal democracy, that extends to conduct which is merely offensive,'' he said.