Barnaby Joyce wields the tea towel in the government's soap opera

As Malcolm Turnbull heads for his time with Donald Trump, which carries its own challenges, he has left behind a very untidy-looking ship of state.

Treasurer Scott Morrison and former prime minister Tony Abbott are trading blows over immigration.

Barnaby Joyce, supposedly on “leave”, is out in the media as part of his fightback against those – including Turnbull – who would like him out of the deputy prime ministership. In an at-home-in-Armidale interview with Fairfax Media, Joyce has spoken about his unborn son, and former staffer and now partner Vikki Campion has produced details of how much she was paid when she moved offices.

The interview took place in the controversial townhouse that Joyce received rent-free from businessman and friend Greg Maguire – which Joyce rather disparagingly describes as “a bachelor’s pad” (and is looking to leave for security reasons).

Abbott’s interventions don’t carry the weight they used to – he isn’t able to cause as much trouble as he once did. Still, when he steps out it is almost always unhelpful to the government.

In a speech on Tuesday he called for immigration to be cut to 110,000, down from about 190,000, criticising the present rate at a time of “stagnant wages, clogged infrastructure, soaring house prices and, in Melbourne at least, ethnic gangs that are testing the resolve of police”.

Treasurer Scott Morrison went out with the takedown on Wednesday. Morrison said he was immigration minister under Abbott and “the permanent immigration intake we have today is exactly the same as it was when he was prime minister. I don’t recall at any time there was any discussion that that should be lowered.”

The “actual facts” were that “the level of permanent migration to Australia has been the same since about 2011, 2012. There has been no change”.

Morrison declared the Abbott policy would cost the budget about A$4 billion to $5 billion over the next four years. “If you did what Tony Abbott suggests, then you would only reduce the proportion that was skilled migration and you’d have a bigger proportion which was family migration which ultimately gets more dependent on welfare.”

Abbott, who has ready and regular access to radio and TV outlets to amplify his voice, was quickly on 2GB declaring: “Scott’s problem is he’s been captured by his department”. In case anyone wasn’t paying attention, “Let me repeat that. That is Scott’s problem – he has been captured by his department.”

Morrison was “echoing the standard Treasury view” but “his view is wrong”, Abbott said. Treasury was always in favour of more migration, but “we cannot let the Treasury’s accounting rules determine what is in our long-term and medium-term best national interests. I mean, we can’t let the tail wag the dog.”

Turnbull can hope the latest iteration of the immigration debate will be over by the time he returns for next week’s sitting of parliament. But he knows the Joyce affair will still be live – and that goes to the heart of his government’s future.

The feeling in the Nationals (though it regularly changes) is that Joyce can hang on to his position for now – if nothing further comes out during what will be an extremely testing week of parliament, especially Senate estimates.

Ahead of parliament sitting, Joyce is putting his side of the story publicly, turning in particular to Fairfax Media because News Corp has spearheaded the charge against him.

In the interview with him and the pregnant Campion, Joyce tells Fairfax: “I don’t want to say have sympathy for me. I just want people to look clinically at the facts and basically come to the conclusion he is not getting a gold star for his personal life, but he has made a commitment, he is with her, they’re having a child, and in a 2018 world there is nothing terribly much to see there.”

“This should be a very simple story – a bloke whose marriage broke down is in a relationship with another person and they are having a child. Now it seems to have gone into some sort of morality discussion. That’s between me and my God. I can understand how Natalie can be angry, absolutely, but how it’s other people’s business, I don’t know.”

With the circumstances and terms of Campion’s employment an issue in the controversy, Fairfax reported that she showed payslips indicating she was paid about $133,000 a year in Joyce’s office, $138,000 when she was moved to minister Matt Canavan’s office, and $135,000 when employed in the office of then Nationals whip Damian Drum. The speculation had been she was paid up to $190,000.

The couple told Fairfax that Canavan and Drum didn’t know about their relationship when Campion went to work for them; Joyce said he hadn’t breached the ministerial code of conduct.

Pressed on when Turnbull first knew, Joyce said: “He never asked any direct questions and to be honest, if I believed it was private, I wouldn’t have told him either”.

Speaking of his unborn son, Joyce said he was “deeply annoyed … that there is somehow an inference that this child is somehow less worthy than other children, and it’s almost spoken about in the third person.

"I love my daughters. I have four beautiful daughters and I love them to death. And now I will have a son. I don’t pick winners, I’m not gonna love one more than another, but I’m not going to love one less than another either.

"I don’t want our child to grow up as some sort of public display. I have to stop it from the start. It’s a fact we are having a child, it’s a fact it’s a boy, it’s not more or less loved than any of my other children.”

The article reported that the only thing Campion would say on the record was that their son’s middle names would be those of her two brothers, who had given support that had “meant so much”.

Campion would not be photographed. Joyce posed with a tea towel. The saga has truly become a soap opera.