Today, Brian Henry, Mr Peters' lawyer, said the case against the Electoral Commission centred around what it should have defined as corrupt practice.
Mr Peters had complained to the commission about the Conservative pamphlet on September 19, including that it had continued to be used after the ASA ruling.
He also complained about an advertisement by Act Party deputy leader and former MP Kenneth Wang, which he said took his comments about the Chow brothers' plans for a brothel out of context, in order to paint him as a racist.
Under the Electoral Act 1993, a person is guilty of corrupt practice who, with the intention of influencing the vote of any elector, at any time on polling day or at any of the two days immediately preceding polling day, publishes material that the person knew to be false.
Mr Henry said the electoral commission responded to Mr Peters' complaint by saying that the corrupt practice provisions only applied if material was first published in the relevant time period.
It was not enough that the material had continued to be published and available during that period.
The Act television advertisement was run during the restricted period, and the ASA ruling came during that period also, but the Conservative material remained online, he said.
Peter Gunn, lawyer for the Electoral Commission, questioned whether its response should be subject to judicial review.
Recent cases examining the commission's position - on whether a Greenpeace website was an election advertisement and the Planet Key parody video - both came after requests for declaratory judgments, which are judgments of a court that resolves legal uncertainty without ordering anything be done or awarding damages.
On the timing of publication issue, Mr Gunn said there was a defence against prosecution if a party put up material on a website earlier than two days before an election, and did nothing further.
"If on the other hand it puts up a billboard or distributes a flyer saying look at our website...that gives it fresh publication."
Justice Mallon said that seemed like a "massive inroad" into the prohibition of what can and cannot be done during a critical period.
Mr Gunn said the effect of the interpretation advanced by New Zealand First was that any political material published, including media reports, long before an election would need to be removed two days out from polling day.
That would create a significant chilling effect.
The law was deliberately restrictive about the corrupt practice provisions because publication earlier than two days before an election provided enough time for falsehoods to be responded to through media or in other ways, he said.
Justice Mallon has reserved her decision.
Mr Peters is currently overseas. The hearing was attended by New Zealand First MP Tracey Martin and staff.
