This week, the Herald revealed that the More FM Breakfast team - including Holt, Stu Tolan and Marc Ellis - gave urine samples to Auckland Drug Screening director Shannon Balzat in an on-air stunt.
It was announced during the segment that Holt and Tolan had both tested positive; Ellis emerged clean.
Neither Holt nor her boss, More FM programme director Ande Macpherson, would comment about the latest incident.
But a source close to Holt told the Weekend Herald that the radio host's judgment was impaired due to "tiredness and emotional exhaustion".
"Hayley was really traumatised after the drug test revelation on Wednesday. She was really embarrassed. Then, the next night, she was at the Joseph Parker boxing bout and had a couple of wines.
"And then she had to get up early and go to Hamilton the next day for the broadcast from the Field Days.
"She was tired, and those couple of drinks obviously hit her. She would never normally do this."
MediaWorks said the incident was out of character for Holt.
"Outside of this incident, Hayley is a professional, reliable and hard-working member of the More FM team, and Friday's behaviour is out of character and has been a one-off incident in her time at the station," said Ms Lorimer.
"We are disappointed these two isolated and unrelated incidents have occurred in such close proximity."
Holt joined More FM in January, replacing former beauty queen Amber Peebles. Bosses said they were relying on Holt's "freshness and spontaneity" to increase the radio show's success.
At that time, Holt told The Diary that she enjoyed the freedom live radio offered.
"I love the atmosphere of radio as a medium. You forget that you're talking and you can have a laugh and give a bit of stick."
• Tomorrow: Hayley Holt talks to the Herald on Sunday.
