The man who took a private prosecution against John Banks says he will do the same against Labour leader David Cunliffe if police do not charge him over a tweet he posted.
The Electoral Commission yesterday referred Mr Cunliffe to the police in relation to the post on social media site Twitter, in which he encouraged people to vote for Labour's candidate in the Christchurch East by-election on the day of the poll.
The tweet said: "If you are resident in Christchurch East don't forget to vote today - for Labour and Poto Williams."
The commission said it referred the matter to police, as it is in breach of rules banning politicians from influencing voters on Election Day.
Today former accountant Graham McCready said he was prepared to take a private prosecution against the Labour leader.
Mr McCready took similar legal action against Act leader Mr Banks, who is now facing a High Court trial on allegations he knowingly filed a false electoral return involving donations to his failed campaign for Auckland mayor.
The Wellingtonian said he would "file a private prosecution without delay or further notice" if police did not charge Mr Cunliffe.
"If a summons is issued I respectfully suggest Mr Cunliffe should resign from Parliament," he added. "Once again the rule of law must prevail."
Mr Cunliffe has 6464 followers on Twitter who would have received the tweet.
In a statement the Electoral Commission said it believed the post constituted a breach of section 197 (1)(g)(i) of the Electoral Act because it was a statement published on polling day "advising, or intended, or likely to influence electors as to the candidate for whom they should or should not vote in the byelection".
Mr Cunliffe said yesterday he had removed the tweet on Saturday as soon as he realised he had made a mistake.
"I understand this is a routine part of the Commission's process. I will be co-operating fully with any inquiry and won't be making any further statement on this matter as it is now part of a formal process," he said in a statement.
Ms Williams won the seat convincingly.
- An earlier version of this story said Mr Cunliffe removed the tweet as soon as the mistake was pointed out to him.