Barnaby Joyce may have shone a seedy spotlight on interpersonal relationships in politics, but it's been a long time coming.

Barnaby Joyce has been forced to issue a grovelling apology to Channel 7 staff who copped his wrath during an expletive-laden backstage tantrum.

It has been revealed the former deputy prime minister was in a foul mood on the night of the New South Wales election, during which he sat on the network’s broadcast panel.

Viewers criticised his aggressive attitude on screen, including his treatment of a female Labor senator, but it paled in comparison to his antics in the green room.

The Australian newspaper today reports Mr Joyce has apologised for his “behaviour and demeanour” off screen after details were leaked by insiders.

It’s understood the former leader of the National Party — who resigned his position last year after it was revealed his mistress and staffer Vicki Campion was pregnant with his child — was furious about how brief his appearance was scheduled to be.

“There were four-letter words aplenty when Joyce first arrived on set and saw his schedule for the night,” The Australian reported.

An unnamed insider told the newspaper: “He had the sh*ts supreme about whether he should even be there.”

A network source told news.com.au word of Mr Joyce’s behaviour had begun to spread last week, and it was only a matter of time before it leaked.

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The firebrand politician’s beef was that he was due to appear on screen for just 10 minutes, despite having flown from his home in Armidale.

He was accompanied by his partner, Ms Campion — he broke off his marriage just prior to the scandal erupting — and their toddler.

“I saw the schedule on the (green room) wall,” Mr Joyce told the newspaper. “Then I saw the closest human being, and I told them what I thought.”

He apologised for his conduct and said he was tired. After the tantrum, Mr Joyce was used for the live coverage broadcast for more than two hours.

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On election night, he was criticised by viewers for his rude treatment of Labor Senator Jenny McAllister, including talking over her.

“I am surprised that you’d not put water on the list of concerns,” Ms McAllister said about the National Party’s poor electoral performance in the state’s west.

“You’ve got these western NSW seats with massive fish kill and a very active conversation …” she continued before being cut off.

“That was because of the Greens … you can’t take water to the south, not have it come to the north and not expect something to die in the middle. It’s the bleeding obvious,” Mr Joyce said as his fellow panellist tried to get her point across.

@Barnaby_Joyce you are so rude!@jennymcallister should not have to ask you if she can her finish remark. Seriously!!! Stop talking over ppl when you don't agree!#NSWDecides @7NewsSydney — Kylie McKelvie (@Kylie_McKelvie) March 23, 2019

“I think the proposition that’s been put is that there’s been complete mismanagement of the water system”, she said, before being again interrupted.

“May I finish my remarks?” Senator McAllister said — a comment met by a shrug from Mr Joyce.

She did continue, barely finishing her sentence before Mr Joyce had his say.

“Finished? You’re wrong,” he said.

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Even one of Mr Joyce’s parliamentary colleagues called out his performance during the NSW election campaign.

Appearing on ABC’s election coverage, Liberal MP Trent Zimmermann suggested his colleague “spend more time in Tamworth and less time on TV”.

His conduct behind the scenes that night was reportedly being described among Channel 7 staff as “green room-gate”.

Mr Joyce has been approached for comment, as has current Nationals leader and deputy PM Michael McCormack.

In a statement, Mr McCormack said: “The Member for New England has provided an apology, which I believe is appropriate.”

Channel 7’s spokesperson did not respond to a request for comment.