A former assistant editor at the Herald on Sunday has denied rumours he was involved in a multimillion-dollar drug ring from Paremoremo Prison and selling P in the newspaper's toilets.

Employment Relations Authority member Rosemary Monaghan is hearing Stephen Cook's claim that he was unjustifiably dismissed by the Herald on Sunday towards the end of last year.

Herald on Sunday editor Shayne Currie told Ms Monaghan the events which led to Cook's dismissal began when police came to the newspaper's office on September 5 last year.

Mr Currie said they identified themselves as drug police and had seen Mr Cook in an unmarked Herald on Sunday car outside a property they had under surveillance.

He gave police the home address of Mr Cook, who was sick that day with influenza. Mr Cook said police visited him and that he was "roughed up".

Mr Cook told Mr Currie at a meeting the following Tuesday, September 9, that he was covering a story about a dispute at a plastics company. He told Mr Currie there was nothing for him or the publication to concern themselves about.

Mr Cook also offered to take a drugs test. Mr Currie told the authority he found Mr Cook's response "puzzling and troubling".

Subsequently, Mr Currie asked Mr Cook to attend a meeting on September 18 with APN executive Rick Neville. Mr Cook attended with his lawyer Chris Comeskey and made a covert audio recording of the meeting.

Both parties agreed that the newspaper wanted a written assurance from Mr Cook that he was not involved in any illegal activity or anything that would compromise the reputation of management or the newspaper.

Mr Cook said he provided this the next day.

But Mr Currie said he also asked for Mr Cook's notes regarding the story he was working on, and a status report on it.

Both parties admitted that was not audible on Mr Cook's recording, although the newspaper said there were several inaudible parts of the recording.

Mr Cook said he received a written request on September 23 asking for the status report and his notes.

He said he felt at this point that he was the subject of a witch hunt and that he lost faith in Mr Currie, especially over Mr Currie providing police with his address.

Following further requests which Mr Cook did not respond to, the newspaper suspended him on October 2 and he was dismissed on December 12.

Mr Cook said he became aware at that stage of rumours that he was dealing in methamphetamine, or P, and that he was involved with a gang, rumours he denies.

The hearing will resume on Monday, when submissions will be made on the remedy Cook will seek if it is found his dismissal was unjustified.