He stands at a microphone, addressing the bar in a speech which starts by thanking those gathered for their efforts in the day's search to find his missing daughter, Tui. But his appreciation quickly turns to a veiled threat, one reinforced by two young henchmen - his tattooed sons, played by locals Jay Ryan and Kip Chapman - who swagger through the bar.
As Mullan's volcanic speech is delivered in successive takes of slight variation, you can feel the tension coming through the wall into the bar next door where I'm observing on a monitor.
After each take, Campion comes in close to Mullan for a quiet word, making suggestions about the right temperature and tempo for his delivery.
Eventually, the director is satisfied. And even before the finished scene is edited into its place early in the series, it's clear that Mullan's character, Matt Micham, will be the latest in a line of complete but compelling bastards created for the screen by Campion. What's also clear is that today Mullan is earning his pay.
"It's a very subtle thing and the thing my experience has given me is knowing that moment when an actor is cooked and the souffle doesn't explode, or collapse, or whatever," says Campion on a break later at the local Glenorchy Hall, the production dining room, where stag-head hunting trophies peer from the walls.
"When it's working, it's happening, I really feel it in my body. I feel myself watching and not doubting."
The gregarious Mullan, whose past directors have included Steven Spielberg and Danny Boyle, has a kind of deep, if perplexed, respect for Campion's way of doing things, and the character she's created for him.
"She's a talky director. Some directors, you can't get a word out of them.
"Today Jane gave me seven different completely contrary directions. F*** it. Jane gets what she wants and that is all I care about. Where Jane is very good is, she knows when you are getting too safe.
"She'll come in just at the moment you are getting a little bit safe and give you something that will make you mess up again and hopefully you'll find something more interesting in it."
Mullan is in a cast which also includes Elisabeth Moss - Peggy in Mad Men - as the lead detective on the case of the missing 12-year-old, Tui (played by young Aucklander Jacqueline Joe), who runs away after it's discovered she's pregnant.
As well as several local faces in supporting roles, including Robyn Malcolm, the series also stars Australian David Wenham as a local cop and Holly Hunter, who Campion directed to a best actress Oscar in The Piano, the haunting Bronte-in-the-bush period film which won Campion the Palme d'Or at Cannes, as well three Academy Awards - one for Campion's screenplay and the other to an 11-year-old Anna Paquin, for supporting actress.
There's another pre-teen girl in Top Of The Lake in a major role, while Hunter plays G.J, the terse, silver-haired androgynous leader of a women's commune, which was among Campion's early ideas for what became the series.
"I thought I would like to write a story about a post-menopausal women's camp, where women went who felt ... they had fallen out of social reality because they were un****able, or unsexy or whatever, and I think being un****able in our society is fairly invisible, because it's such a sexualised society.
"I liked the idea of them as old Vietnam vets, but love vets, soothing their wounds but not being able to give up enough to know their day is done."
Campion says Hunter's leader was influenced by a yoga guru she found inspirational. But she was a reluctant recruit.
"Holly was terrified. Holly rang me up to say she didn't think she could do it - 'how can I do this?' - and I didn't seem to hear her.
"She said, 'Jane, I am used to being your leading lady' and I was 'no, no she's the most amazing character in the whole piece. You'll be great. You'll be able to do something with it' and somehow I talked her into it without realising she was trying to dump me," chuckles Campion, in her infectiously booming laugh.
As well as a Campion-Hunter reunion, the largely BBC-backed production is her first work in New Zealand since the 1993 film.
That was after Campion first came to attention with debut feature Sweetie and her Janet Frame screen biography An Angel At My Table, which had originally been destined for television before its acclaimed release as a movie.
Now, Campion, our most distinguished and literary-minded maker of art cinema, is back doing television after seeing the likes of HBO's edgy western, Deadwood, and realising that there "was TV out there that was very daring and amazingly well done".
She convinced the BBC and, initially, Australia's ABC - which pulled out when Campion determinedly cast American Moss in the lead, rather than an Australian actress - with an idea for a crime mystery story to which she could add her own distinctive touches and texture.
It's a genre she's tackled before, in the 2003 thriller In The Cut, which, like her other contemporary work, 1999's Holy Smoke!, confounded audiences with its confronting eroticism.
As Mullan says: "The script is full of that Campion-esque off-centre weirdness. She's a weirdo. She writes good weird."
Her choice to set Top Of The Lake against the Queenstown area wasn't just because of the scenery. She's a local, of sorts. Long-based in Sydney, Campion has a cottage on the high country Rees Valley Station further up the road from Glenorchy, where she's lived and written on and off over the years.
"I don't think you are really a local until you live there all year round. I am certainly very attached, after 40 years of coming and going and my daughter going to school there, even. I feel very privileged to have some strong connections to at least a couple of families in the area."
With a $15 million budget, the six hours of Top Of The Lake were co-written with novelist-screenwriter Gerard Lee, an old mate who co-wrote Sweetie, and half of the six episodes are co-directed by young Australian commercials director Garth Davis, a dab hand with helicopter camerawork and technology. He would have been directing that day's pub scene, but for the impending arrival of a baby.
The initial idea and the casting choices were hers, but Campion figured early on she needed to spread the workload.
"I just couldn't manage it. Before, when I made Portrait Of A Lady, which was three hours ... halfway through that I was, 'I am never, ever going to do this myself again'."
Many months after that day in Glenorchy, and a few weeks after Top Of The Lake launch screenings at the Sundance and Berlin Film Festivals, a relaxed-sounding Campion is talking down the line from India.
After finishing editing the series before Christmas and the festival appearances, she's headed to Jaipur in the northern state of Rajasthan to a favourite yoga retreat for a holiday she hopes will be the start of an extended break, after the run of Top Of The Lake's writing/casting/filming/editing deadlines.
She's heartened by the reaction at the festivals. At Sundance, they screened the entire six hours - "I expected to turn around and see no one there" - to shining reviews. She's hoping if people miss the pay-TV broadcast of the series, they might put aside a weekend for a binge-viewing on DVD and take it all in, like a novel.
Asked what Top Of The Lake says about where she, at 58, is in her life and career, Campion says it's a mature work but she won't be prodded into self-analysis about it.
"I never make it my job to worry about myself like that. I just discover what comes out of me and what I am going to enjoy or find fascinating. I work with the fiction that I am attracted to ... then I work to make it solid and a good shape and all that sort of thing - I don't think 'Oh, what does this mean about me?'
"Of course, it does [mean something] but I leave that to others to work out."
Well, after her sweetly chaste last feature Bright Star - about poet John Keats and Fanny Brawne, which many critics thought her best work since The Piano, even if it went largely unheralded - the brooding transgressive world of Top Of The Lake might actually be seen as a return to familiar territory. And it's fitting she should do that in New Zealand.
After all, like The Piano, Top Of The Lake takes place somewhere near the edge of the world.
"It's more about a community at the end of the line, at the edge of things. People who have chosen to live as far away from the centre as they can ... and often they do it because they are in love in the landscape."
She thinks, or possibly hopes, the home town crowd will be savvy enough to realise the series is a work of fiction and isn't a commentary or a literal representation of the area where it was filmed.
"It's called Lake Top deliberately because it doesn't represent any town I know, and we want to take people away from thinking this really goes on there. I know it doesn't really go on there."
And while it may have a crime-mystery plot engine, like many of Campion's past works, it's also a setting for a psychological - and often physical - battle of the sexes.
There is Micham and his boys facing off against the female commune which has set up in "Paradise" - not the idyllic spot near Glenorchy itself, but inspired by it and filmed down the road at Moke Lake - on land they consider is theirs. There is Moss' troubled detective, a former local, dealing with Wenham's boys' club of a constabulary and an ex-boyfriend with connections to the case. And there's young Tui, pregnant and unwilling to divulge who the father might be.
"This is the final battle!" Campion hoots when it's suggested those six hours of screentime give her time for a truly epic gender conflict.
"This is the Lord Of The Rings version - the patriarchy and the matriarchy, they're really going to fight it out."
Her own campaign done, Campion now finds herself wondering what to do next among the other unnamed film projects she has backed up.
But she has a little more freedom these days and doesn't have to be based in any one place anymore, since her teenage daughter, Alice Englert, finally left home and got a job - as a movie actress.
She's just graduated from indie films to post-Twilight witch fantasy Beautiful Creatures, which her mother hasn't yet seen.
So, no wise maternal warnings about the dangers of the movie biz?
"It's her life. She's very good at it. She's my daughter, what can I say? If she gets good reviews, that's great, but she is always going to get good reviews from me."
Top Of The Lake starts on March 25, 8.30pm on UKTV.
