The United Nations' special rapporteur on racism has condemned Australian politicians from major and minor parties whose statements are contributing to an increase in "xenophobic hate speech" and negative views about migrants.

Mutuma Ruteere has also warned that political leaders who do not denounce such views are tacitly contributing to the normalisation of hard-right and racist opinions.

Mutuma Ruteere says Australia is not unique among western democracies in grappling with popular support for parties with discriminatory policies and racist views. Credit:EVAN SCHNEIDER / UN

"If they do not speak out they lend legitimacy to them. It's very easy for darkness to drive out the light. It's very easy for the bad to demean the good. It's much harder to clear out the political space once it's infected by racists," Mr Ruteere said in Canberra on Wednesday.

Mr Ruteere was finishing a visit to Australia, the first by someone holding his position in 15 years. He comments will form the basis of a report he will deliver to the United Nations Human Rights Council next year.