The mother of the man suing Colin Craig for defamation has told the court Mr Craig sought to ruin him with a leaflet containing false allegations.
Taxpayers' Union executive director Jordan Williams is suing Mr Craig for defamation over comments he made at a news conference and in a widely distributed leaflet in July last year.
Mr Craig's press secretary, Rachel MacGregor, resigned just before the 2014 election.
Mr Williams gave evidence on Friday, saying he had given a poem written by Mr Craig for Ms MacGregor to Whale Oil blogger Cameron Slater.
He said he was trying to set the record straight for Ms MacGregor's benefit, after hearing Mr Slater intended to publish a story suggesting Ms MacGregor was obsessed with Mr Craig.
Victims' advocate Ruth Money also gave evidence today, and said she believed Ms MacGregor was a victim of sexual harassment.
She told the jury she had been acting as Ms MacGregor's support person.
Ms MacGregor had survived some nasty stuff, she said.
Under cross-examination by defence lawyer Stephen Mills QC, Ms Money said she had concluded that Ms MacGregor had been sexually harassed by Mr Craig, who was a powerful man who had acted inappropriately.
Ms Money said Mr Craig had not just sent Ms MacGregor one letter or card, and that his behaviour was constant and predatory.
Mr Williams' mother, Megan, at times held back tears as she gave evidence in the High Court in Auckland this afternoon.
She told the jury she believed Mr Craig had tried to ruin her son, by distributing a leaflet containing false allegations about him to homes across the country.
"How can he do this and get away with it," she said.
"All Jordan did was tell another person that Mr Craig was behaving in an unacceptable manner regarding Rachel. As far as I can see that was the truth, and Colin Craig has gone out to ruin Jordan as revenge."
No smear campaign against Mr Craig, former party member says
Speaking earlier, former Conservative Party member John Stringer said there was no smear campaign against Mr Craig.
There was no dirty politics strategy against Mr Craig and it was all in his head, he said.
Mr Stringer said he was one of a number of people in the party concerned that Mr Craig was writing secret love letters to Ms MacGregor.
Mr Stringer said Mr Craig had told him that Ms MacGregor was obsessed with him.
He told the jury he and other board members had lost confidence in Mr Craig and hoped to roll him as leader, and that the rumours and allegations about Mr Craig had caused the party to implode.