The United Nations rights chief called Friday for concerted global efforts to rein in hate speech, including more effectively countering "mega spreaders" of hateful and dangerous messages.

Ahead of the International Day for Countering Hate Speech on Sunday, Volker Turk insisted "multifaceted and well-resourced efforts" could help rid the world of the scourge.

"We know that the spread of hate is used by those who want to sow divisions, to scapegoat and to distract from real issues," Turk said.

Social media in particular had become "remarkably fertile ground for hate speech, providing it with both unprecedented reach and speed", his statement said.

"Hate breeds bigotry, discrimination and incitement to violence," he said.

The UN High Commissioner for Human Rights acknowledged, "There is no silver bullet, no switch to flip that will rid our world of hate."

But he insisted that investing in a range of targeted measures would make it possible to limit the spread of hate speech and to hold accountable those who spread it.

Among other things, companies should be held responsible for what they are, and what they are not doing, in respect to hate speech.

"More also needs to be done to address mega-spreaders -- those officials and influencers whose voices have profound impact and whose examples inspire thousands of others," he said.

"We must build networks and amplify voices that can cut through the hate," he said, pointing for instance to an initiative engaging religious leaders to try to respond to hatred and incitement to violence.

He also called for greater investments in effort to combat hate speech in languages other than English, in digital and media literacy programmes and independent fact-checking.

Turk meanwhile cautioned that the battle against hate speech can be misused.

"Globally, the spread of hate speech-related laws being misused against journalists and human rights defenders is almost as viral as the spread of hate speech itself," he said, pointing to how broad laws provide licence to states to censor speech they find uncomfortable and to threaten or detain those who dare question policies or criticise officials.

"Rather than criminalising protected speech, we need states and companies to take urgent steps to address incitement to hatred and violence," he said.