The incident was witnessed by another Ministry of Justice employee, Mr Billington said.
Ms O'Brien's version of events was backed up by the findings of a Porirua District Court judge, who in February found Creser guilty of assault and later sentenced him to 100 hours' community work.
Creser then appealed against his conviction at the High Court, which dismissed the appeal.
Mr Billington today asked Auckland District Court Judge Grant Fraser to dismiss the charges brought by Mr McCready, saying two judges had already found that Ms O'Brien had not assaulted Creser, rather she was the one who was assaulted.
"To allow the matter to proceed would be an abuse of process," Mr Billington said.
Mr McCready said his client was simply trying to serve papers on Ms O'Brien. However, in light of the Porirua District Court and High Court judges' findings, he said that the private prosecution was futile.
He told the court that when he heard Siemer was involved in the case it caused "alarm bells" to ring. "It was bound to end badly."
"I won't waste your time any more," Mr McCready said to Judge Fraser, accepting that the charges must be dismissed.
Judge Fraser said two judges before him had already found that Ms O'Brien was not the aggressor, "but simply responding to an assault on her" and subsequently dismissed the charges.