NSW police have charged one of Australia's most prominent far-right extremists with allegedly making repeated and explicit violent threats against a Melbourne journalist and lawyer.

Nathan Sykes, a prolific online troll and a lieutenant of Australia’s most prominent white supremacist Jim Saleam, has been charged with multiple offences, including using a carriage service to menace and to issue threats to do serious harm.

Alleged neo-Nazi troll Nathan Sykes after his arrest in Sydney. Credit:SMH

He was released on bail on Friday afternoon under very strict conditions, including that he cannot travel to Victoria or contact the journalist he allegedly threatened, Luke McMahon.

The decision to arrest and charge Mr Sykes was made by senior NSW police just hours after The Age and Sydney Morning Herald revealed how officers had shelved an investigation into the threats.