In a dramatic hearing in the NSW Supreme Court on Tuesday, lawyers for the media company released a string of emails in which former executive assistant Amber Harrison said she was "out to get" Mr Worner.

The company is seeking an order permanently restraining the 39-year-old from publishing embarrassing details about her two-year affair with the Seven chief executive, which ended in 2014.

But Ms Harrison's barrister told the court she was far from a "venomous harridan setting up poor Mr Worner" and Seven did not need to be protected from an "unemployed woman living down in Melbourne".

In an email to a colleague, read in court on Tuesday, Ms Harrison promised to wage a campaign aimed at "finishing" and "destroying" their "idiot boss".

"He knows I am now out to get him," Ms Harrison said in the 2014 email.

"This is now war."

In another email, Ms Harrison said she had "zero, apart from a thousand texts from someone I'm about to blow the head off".

"He really shouldn't have ignored me. Big mistake. Huge," Ms Harrison said.

Ms Harrison, a former executive assistant to Seven's Pacific Magazines boss Nick Chan, wrote that she had launched a "reign of terror" after her affair with Mr Worner came to an end.

She has engaged Melbourne barrister James Catlin – who was a political advisor to former Victorian premier and current Seven board member Jeff Kennett – to fight the court order.

"This is a defamation injunction parading as a confidentiality injunction," Mr Catlin said.

He said emails from Ms Harrison were "very few in number from a woman scorned, you might think".

He told Justice Robert McDougall the media company was taking "maximum advantage of the gag on Ms Harrison effectively to vilify her", including in comments made by Mr Kennett.

A "billionaire and owner of a television station [Kerry Stokes] and an ex premier of Victoria" should have told the court they would use the gag order to launch a "full-scale media campaign" and "let rip with both barrels" against Ms Harrison, he said.

Seven took urgent legal action last Monday to stop Ms Harrison posting any information about the company on her Twitter account, which was set up to air her grievances.

The Supreme Court granted a temporary gag order last week and the company is now asking the court to extend the order on a permanent basis.

On Tuesday Justice McDougall extended the temporary order until the final hearing of the case, which will not be before March.

The final order would prevent Ms Harrison making any comments about Seven or "otherwise bringing [the company] into disrepute".

Ms Harrison believes she has been mistreated by the company and her public campaign stepped up a notch after the board decided an independent review of Mr Worner's behaviour cleared him of any wrongdoing.

In documents filed in court, Ms Harrison said the affair started in December 2012 when the pair worked in separate offices in Sydney.

She said the relationship became "increasingly volatile" when she was transferred to Seven's offices at Jones Bay Wharf where Mr Worner worked.

Ms Harrison said the new working arrangements made her uncomfortable because she heard "gossip" about Mr Worner's personal life, including that he had "slept with another woman", and she believed he was "ignoring" her.

On June 25, 2014, she sent an angry text to Mr Worner about the other woman, saying "F--k me Tim. You are right. You are busy."

She was advised on July 11 that "unexplained expenses" had been identified on a corporate credit card she controlled.

Ms Harrison said she suspected the investigation was initiated because of the "increasing volatility" of her relationship with Mr Worner.

Seven's barrister, Andrew Bell, SC, told the court this was a "private dispute relating to a contract of employment and a deed" signed by Ms Harrison before she left the company.

She "freely and voluntarily entered into" the agreements including promises not to make comments in public and was paid "significant sums of money" as the "price", Dr Bell said.

But Mr Catlin said Seven had "ceased making any payments whatsoever" to Ms Harrison from March 2015, and $242,500 remained outstanding.

"She has respected the confidentiality while not being paid the price," Mr Catlin said.

Dr Bell said Ms Harrison had assembled confidential information from the company for her own "disgraceful purposes", including taking screenshots of documents relating to an Australian Federal Police raid on Seven's headquarters over the Schapelle Corby deal.

He told the court screenshots were one way to "camouflage the theft of documents".

In a further email read in court, Ms Harrison said she was "powerful now" and had "just got everything".

"New ball game," she added.

​Mr Catlin said the injunction was futile because it was already "out there" that Mr Worner had been "unfaithful to his office and unfaithful to his wife" and the release of more texts messages was not going to "do anything".

Sydney barrister Matthew Lewis appeared for Fairfax Media and News Corp to argue the gag order should not prevent journalists seeking comment from Ms Harrison in response to claims by Mr Kennett and others.

But Dr Bell said Ms Harrison had "fomented the controversy" and "created the story" and would continue to do so unless the court restrained her.