Hosking, who won best talk presenter for his breakfast show at this year's NZ Radio Awards, is also well-known for his time hosting Seven Sharp.
After four years, he filmed his final show as host in December 2017.
A spokesperson for NZME - owner of Newstalk ZB and publisher of the Herald - said the matter was subject to court proceedings and therefore the company was not in a position to make a public comment about the case.
"NZME values the health, safety and wellbeing of our people above all else," he said.
"We have robust protocols and processes in place to ensure all of our employees are kept safe, including the ability to apply additional security and protection measures if and when required."