As an Australian working abroad, Cate Blanchett never found it easy talking about her home government – in particular, the trauma it has inflicted on asylum seekers in need.

“They knew nothing about the Tamils on the roof, nothing about children sewing their lips together [in detention centres],” Blanchett says of her American friends. “They would actually start with nervous laughter because they thought I was exaggerating.”

We meet in Adelaide in 2019, where she is filming scenes for the upcoming series Stateless. Premiering next week at Berlinale before landing on the ABC on 1 March, the six-episode show – co-created by Blanchett, Tony Ayres and Elise McCredie – takes a deep dive into Australia’s controversial immigration policies.

“There’s a profound anxiety about where we’re all heading and the erosion of empathy and, of course, that’s the space where the drama takes place,” Blanchett says, during an interview with all three co-creators. “None of us are interested in preaching to the converted.”

When I meet Blanchett she looks the epitome of geek chic: a navy shirt flecked with tiny white stars, tucked into cropped jeans; a mannish blue pinstripe blazer, oversized trainers and chunky glasses. She is thoughtful and intellectual, with a willingness to examine ideas. She asks as many questions as she answers.

Blanchett explains that inspiration for the TV show – in which she stars alongside other heavy-hitters including Dominic West (The Wire), Yvonne Strahovski (The Handmaid’s Tale) and Jai Courtney (Suicide Squad) – was the story of Cornelia Rau.

That story was well-reported at the time. In 2004, Rau was sedated, put in restraints and transported against her will to South Australia’s Baxter detention centre. Authorities suspected she was an illegal immigrant; in fact, Rau was a German citizen and Australian permanent resident who suffered from a mental illness.

It was only four months later, after her family, who had reported her missing, recognised her in the media, that she was finally granted her freedom.

In Stateless, Strahovski plays Sofie, a German-Australian air hostess who is also mentally ill. The show spans everything from Sofie’s time in a cult to her breakdown and unlawful imprisonment.

Rau’s story is “so rich and so complicated and so painful and so unlikely and so surprising and bewildering that you could make a series in itself”, explains Blanchett. But, she adds, “there were so many things we wanted to talk about”.

Stateless is smart, intelligent viewing – less a star vehicle and more a detailed character study on the psychological repercussions for four characters who all end up, in one way or another, inside a barren, soulless detention centre in the dusty South Australian desert.

They include Ameer (Fayssal Bazzi), an Afghan asylum seeker trying to escape the Taliban with his family; Cam (Courtney), a working-class father of two who attempts to carve a better life for himself by becoming a guard; and Clare (Asher Keddie), an ambitious, hard-nosed bureaucrat from Canberra who is under pressure to sort out a PR mess as human rights abuses are leaked to the press.

Other moments are also eerily reminiscent of real life: from the tragic sinking of an asylum seeker boat bound for Christmas Island in 2011 (which left one teenage survivor without a mother or sister) to three Iranian asylum seekers who protested on the roof at Baxter after having been detained for four years.

It is Sofie, however, played with eye-wincing rawness by Strahovski, who becomes the series’ Trojan horse. As co-creator and writer Elise McCredie explains: “She leads us into this world … We’re opening the door through Sofie’s eyes.”

Set in the early 2000s, when Australia started its policy of turning back refugee boats, Stateless is pinned together by the question of identity. The act of seeking asylum, insists McCredie, “Really interrogates who you are. People in long-term detention, their identity gets stripped away.”

Madness becomes a theme, too, as many of the characters begin to lose their grip on reality. As Blanchett sees it, madness also extends to the systems of government and institutionalisation that have taken hold of Australia and beyond.

“You’re living in a system that has gone mad,” she declares, leaning forward intently to plead her case. “The absurdity of what is going on in these institutions! In the prison system, the mental health system, in the detention centres!”

Adding an extra layer to the drama – and drawing out these threads of madness and identity – is Gopa, a cult Sofie is drawn to early in the series. It resembles a real sect in which Rau became entangled: Kenja, created by Jan Hamilton, an actress, and Ken Dyers, a world war two veteran, who offered two-way meditations for cash. (Dyers was later charged with sexual offences against four underage girls.)

In Stateless, Gopa is led by a husband-wife team, performed by West and Blanchett, who promise transformation through song, dance and sinister one-on-one healing sessions, which have a dark sexual undertone.

For Blanchett the idea of a cult becomes “a metaphor for people who are seeking change so they’re at a profound point of vulnerability”.

“They enter a cult to find self-realisation and they emerge in pieces. That becomes a wonderful metaphor for how dislocated the political system is from the people they’re meant to serve.”

West plays Gordon a man, as he puts it, of the “most astonishing mediocrity” who nonetheless manages, through a combination of cheesy empowering talk and bullying malice, to get rich and get kicks, all the while controlling his charges.

Gordon is also fond of pastel slacks and blow-dried hair. “It’s been really fun doing it, especially with Cate, because we wear the most appalling clothes,” riffs West, slouched on a chair in Adelaide with one leg propped up on a sofa, his shirt unbuttoned. “But actually the scenes that I do are deeply distressing.”

West had never heard about Australia’s immigration policies before taking on the role. “Most people in the UK assume Australia is quite enlightened and progressive about everything and also that it has a lot of space and, like many countries, is based on immigrants and is pretty welcoming to them – so it’s shocking to read about what is happening on offshore detention centres,” the British actor says.

The issues, he adds, “aren’t really being talked about except in very simplistic terms. People are being duped into thinking it’s an easy political football, an easy political point to be scored against refugees”.

Stateless, its creators hope, will succeed where news reporting often fails: by gripping the public and holding their attention.

And through displaying abuses through the eyes of Sofie – a blonde, blue-eyed Aussie who comes from a nice suburban home – Stateless seeks to show this is a story that doesn’t affect the “other” but all of us.

Or, as an asylum seeker puts it to Sofie in the detention centre: “They will want to know why someone who looks just like them is trapped in a place like this. You could be our voice. The face of our suffering.”

• Stateless premieres at Berlinale on 26 February before debuting on the ABC on 1 March.

• This article was changed 21 February to clarify the context of a quote used in the headline.