A man who privately prosecuted Labour MP Trevor Mallard for assault is himself before the court.
Graham McCready, 67, appeared in the Wellington District Court on Wednesday charged with blackmail.
The charge sheet alleges that Mr McCready threatened to disclose a defamatory, libellous document relating to another person, with intent to cause loss to that person.
No further details of the charge were revealed. Mr McCready was remanded on bail to reappear in court in April.
In 2009, Mr McCready prosecuted Trevor Mallard after the MP was involved in a stoush with National MP Tau Henare.
Mr Mallard pleaded guilty to the lesser charge of fighting in a public place and was ordered to pay $500 to the Salvation Army Bridge programme, which deals with alcohol and drug dependency.