TVNZ will tomorrow begin disciplinary proceedings against head of news and current affairs Bill Ralston for "very serious" and "quite unacceptable" conduct, says chief executive Rick Ellis.

The move follows an expletive-laden telephone call to the Herald on Sunday last week by Ralston following a request for information for a story about a relative.

In an earlier cordial email, Ralston had provided detail about the family member - a cousin living an itinerant lifestyle in Auckland - but shortly after rang the newspaper and verbally abused the reporter.

TVNZ chief executive Rick Ellis met Ralston on Friday afternoon to discuss the telephone call and confirmed yesterday disciplinary action would follow.

Ralston, who later apologised to the newspaper, was "deeply remorseful", but the behaviour was still unacceptable, said Ellis.

Ellis was not prepared to discuss what disciplinary action was planned against Ralston, saying only that the matter was "very serious" and the language "quite unacceptable". He was waiting for advice from the TVNZ human resources department about the executive's contract, the policies of the company and the relevant processes as set out by the Employment Relations Act.

He would not comment on whether Ralston would lose his job.

"I consider it to be very serious and quite apart from whether you were the media, which is even more distressing, that sort of behaviour, fullstop, is unacceptable," said Ellis.

"It is not what I expect of anyone in the company, least of all my leadership, and it is not what the public should expect of a public institution such as TVNZ. I am taking it very seriously."

With a background in television, radio and print, Ralston has been a journalist for nearly 30 years.

He was appointed head of news and current affairs at TVNZ in 2003 by Ian Fraser, with the board at the time welcoming his "bit of mongrel" attitude. Since then he has overseen sweeping changes to the formats of TVNZ's news bulletins, but not without casualties. Among the high-profile departures have been screen favourites Judy Bailey, Richard Long, April Ieremia, Paul Holmes and Mike Hosking.

This is not the first time Ralston's comments have landed him in hot water. His most infamous remarks were directed last year at former Prime chief executive officer Chris Taylor who he suggested should pour petrol over himself and throw himself off Auckland's tallest building.

In October last year Ralston told the Herald on Sunday it was almost time for him to leave the job.

"I'll probably get it all sorted and when I'm happy with it, I'll wander off and go back to doing what I was doing, which was enjoying myself. A couple more years would be fine, as far as I'm concerned; a year or so. That's the end of the challenge."