The Treasurer, Joe Hockey, has told the Federal Court his father broke down in tears when he spoke to him after headlines emerged last year that read "Treasurer for sale".

Mr Hockey has been giving evidence during his defamation case against Fairfax Media over a series of articles published in newspapers and on the internet relating to his involvement with the Liberal Party fundraising group, the North Sydney Forum (NSF).

He is taking legal action against the Sydney Morning Herald, The Age, The Canberra Times and their online services.

Mr Hockey said he was "absolutely devastated" when he bought a newspaper in the Canberra suburb of Manuka last May.

"I saw the front pages. I was just stunned and the newsagent says 'What's all this about?' And I just shook my head."

The Treasurer said his father is frail and there was doubt in his voice when he spoke to him on the telephone.

"He broke down in tears when I rang him," he said.

Mr Hockey revealed his daughter later asked if someone was trying to "buy" him.

The Treasurer told the court "the only thing you walk out of politics with is your reputation ... my view is there must be integrity in the political system."

He said he did not rely on the NSF to influence his decisions.

Social media message viewed by over 250,000 people

The articles in the Sydney Morning Herald reported the NSF was not fully disclosing its activities to the electoral funding authorities.

A social media message on Twitter with the headline "Treasurer Hockey for sale" was viewed by 279,000 people.

The court heard a series of email messages was exchanged between the editor-in-chief of the Sydney Morning Herald Darren Goodsir, Fairfax chief executive officer Greg Hywood and the political reporter, Mark Kenny.

One email sent by Goodsir in May 2014 read: "I have long dreamed of a headline 'Sloppy Joe'".

After Mr Hockey requested an apology, the court heard Hywood said: "Be thankful you are getting what you are. You're lucky when an issue like this gets to court you're not another Craig Thomson."

Thomson is a former union power broker who was convicted of fraud and theft over misusing his union credit card.

Mr Hockey's lawyer Bruce McClintock SC said the article on May 5, 2014 was motivated by "petty spite" over an earlier apology by Fairfax Media to the Treasurer about a different matter.

He told the court his client had "a spotless reputation for integrity and no-one has ever suggested that he has been for sale before".

Mr McClintock said the article, banners outside newsagents and Twitter messages represented "a clear allegation of corruption".

"There is no innocent construction for those words, 'Treasurer Hockey for sale'," he said.

He said even former prime minister Malcolm Fraser sent a message on social media about the articles.

"Hundreds of thousands perhaps thought the Herald, The Age and The Canberra Times were asserting that my client is corrupt," Mr McClintock said.

The case is set down for two weeks but Mr Hockey's lawyer told the court the matter may be concluded by next Monday or Tuesday.

The case continues.