That extends to social media posts - at the last election the Electoral Commission referred a number of posts to the police, including tweets endorsing National from rugby players Israel Dagg, the late Jonah Lomu and rower Eric Murray.
Police have issued warnings but have not prosecuted people over such postings.
A spokeswoman for the Electoral Commission told the Herald that it was still assessing complaints and had not yet made any decision about Plunket's posting.
The complaints come after it was revealed Plunket has been appointed as a member of the Broadcasting Standards Authority (BSA) from October 1.
Minister for Arts, Culture and Heritage Maggie Barry made the appointment on June 1. However, it was only announced in a gazette notice this month.
Barry said that was because Plunket's start date was delayed to reflect his employment with Top during the election period.
Plunket will be one of four members. The others are chairman Peter Radich, Paula Rose and Te Rau Kupenga. He is replacing his former partner Leigh Pearson. Her remuneration in 2016 was $22,420.
The BSA oversees broadcasting standards regulations in New Zealand, and provides a place for members of the public to lodge a complaint if they feel they've been mistreated by a media organisation.
Plunket is an outspoken former host of news shows on Radio Live and Radio NZ. He attracted controversy for some of his social media postings during the election campaign, including criticism of Herald contributor Lizzie Marvelly.
He himself had two BSA complaints laid against him in 2015 after calling author Eleanor Catton an "ungrateful hua". The complaints were not upheld.
Plunket did not return a request for comment. Barry said his nomination went through a broadcasting sector process, and due diligence was done by officials and the BSA chair.
"Media personalities are often outspoken and combative and media organisations are used to working in a robust environment. His practical experience of the sector brings essential knowledge to the BSA board," Barry said.
"His name was one of several nominations put forward by two media organisations. He has 30 years broadcasting experience and a broad general knowledge of the sector."
Barry said Plunket's appointment went through the normal committee and Cabinet process, "and he was considered to be the best candidate for the position".