Former Attorney-General Christian Porter's lawyers have applied to keep radio and television broadcasting company The ABC's defence confidential.

There's also a hearing into whether parts of the ABC's defence should be struck out entirely.

Porter is suing the ABC as well as journalist Louise Milligan in the Federal Court after a story about an anonymous letter being sent to the Prime Minister contained a historical rape allegation from 1988.

The article did not name the Attorney-General as the subject of the complaint, but Porter's team claimed that he was easily identifiable.

Nearly a week after the article was published, Porter came forward and identified himself.

The woman who made the claims has since taken her own life.

As the case is being heard in Federal Court, Porter can ask the court to strike out parts of the ABC's defence on a range of grounds, including that the defence contains scandalous, frivolous or vexatious material or is likely to cause prejudice or embarrassment.

The ABC filed its defence with the court on Tuesday, but it has not yet been made public due to Porter's lawyers applying to have some of the material omitted.

In a statement, the ABC says it "supports having all materials in these proceedings, which are in the public interest, open to public scrutiny".