James Patrick Hodgson, 51, pleaded guilty in the Supreme Court in Launceston on Friday to one count of perverting the course of justice.

His partner made a statutory declaration to police in 2017 which lead to Hodgson being charged with carrying out a common assault against her.

Just over a week after he was charged, Hodgson called the woman and "demanded she change her statement" to instead say that she provoked the situation and that she would not be a witness.

The assault charge was dismissed in the Magistrates' Court.

Justice Robert Pearce said victims were "entitled to protection against pressure" and the actions of Hodgson were an example of the challenges facing police in investigating family violence matters.

Justice Pearce said the lack of an implicit threat during the phone call lowered its severity.

"Although what you said was expressed in strong terms, it was not accompanied by any threat," he said.

"You have accepted responsibility for what you did and are sorry for it."

Hodgson was convicted and placed on a community corrections order for nine months with 70 hours of community service.