Television New Zealand and the Radio Network say they are carrying out reviews of their handling of former employee Tony Veitch.
An assault complaint has been laid against the sports broadcaster by his former partner Kristin Dunne-Powell over an incident in 2006, police said.
Mr Veitch resigned from his Auckland-based radio and television jobs on Thursday and last week admitted "lashing out" at Ms Dunne-Powell during a domestic incident.
Television New Zealand chief executive Rick Ellis says four senior executives knew only of a "minor fracas" involving Mr Veitch and had not quizzed him further. No disciplinary action will be taken against them.
Mr Ellis says a review is being carried out into how TVNZ handled the matter and there will be changes to management and employment practices.
He did not derive any pleasure from accepting Mr Veitch's resignation, saying he was employed for about 13 years and was a talented and hard-working broadcaster.
Mr Ellis says the controversy has been a blow to the organisation and it would have been unrealistic for Mr Veitch to stay on.
His sentiments are shared by the Radio Network's general manager of talk programming, Bill Francis.
"He thought it was untenable given all the media furore around what may or may not have happened and he believed that it was the best decision to resign," Mr Francis says.
Both companies say Mr Veitch will not get a golden handshake and will only be paid for the standard notice period.
In a statement released on Thursday, Mr Veitch says untrue statements have made his on-air roles at TVNZ and The Radio Network "untenable".
He says he has been honest with his employers and tried to do the right thing.
Mr Veitch says he needs to take stock of his life and spend time with his family before he makes decisions about his future. He says he is continuing to undertake counselling and that he has loved his job at TVNZ, which he describes as "his life".
Ms Dunne-Powell says she will not be making any further comment as the matter is now before the police.
A friend and former colleague of Mr Veitch says he is trying to come to terms with what has happened.
Brendan Telfer told Morning Report on Friday that Mr Veitch has been the subject of "trial by media" over the past 10 days.
"I don't dispute the fact that there probably was a legitimate story there in the first place. But I think these monstrous attacks on his character, based on hearsay and gossip and rumor is not what I consider to be a proper journalistic moral code."
Mr Telfer says he is pleased a police investigation is under way, but finds it difficult to believe Mr Veitch will be able to resume his activities as a broadcaster in the short term.