"For many years my visual library of Canberra had come from, you know, that year 6 visit to Old Parliament House," she admits.

But when the television scriptwriter returned to Canberra with a view to setting and filming a political thriller in the city, she began to see her nation's capital in a dramatic new light.

"Coming back and looking at it anew, it blew me away as such a beautiful, sophisticated international city with a lot going on beneath the surface."

Which is precisely how The Code, Birse's compelling new six-hour drama for the ABC, depicts Canberra – from the top of Parliament House's familiar flagpole to the basement interrogation cell of a fictional security intelligence agency's HQ.

Starring David Wenham, Aden Young, Lucy Lawless, Adam Garcia and Dan Wylie, the series follows two brothers – one a young press gallery journalist for an upstart website, the other a computer hacker with high-functioning autism – as they unravel a deadly plot that reaches from a shadowy international biotech company's highly classified research facility beyond Broken Hill all the way to the prime minister's office.

It's a slick, smart, suspenseful political hacktivist conspiracy, and the capital's landmark buildings, striking skyline and suburban streetscapes make grand settings for its gripping drama.

Birse, whose TV writing credits include cop shows Rush and Wildside, medical drama G.P., whodunit caper Miss Fisher's Murder Mysteries, brothel drama Satisfaction, teen soap Blue Water High and twentysomething favourite Love is a Four-Letter Word, said Canberra provided the perfect backdrop.

"It always had to be Canberra given it's the heart of power and where the decisions are made," she said. "But so often with the logistics of making film and television the nuts and bolts sit mostly in Sydney or Melbourne.

"And yet we all dreamed of how extraordinary it would be if we actually shot it in Parliament House. How grown up it would be if we could tell a potentially uncomfortable story about power and governance in the real place instead of pretending."

The Code was shot at locations across the city, as well as in and around Parliament House, in September last year.

From gun-toting counterintelligence officers prowling the shores of Lake Burley Griffin near the Carillon to media-manipulating political staffers stalking the corridors of power on Capital Hill, the action unfolds at such familiar places as the ANU campus, the Shine Dome, the streets of Red Hill and the courtyards of New Acton.

The occasional glimpse of the Canberra Times masthead – including a copy folded under the arm of Wenham's shady Deputy Prime Minister and Foreign Minister, Ian Bradley – adds another degree of authenticity to the intrigues.

The Code's sleek, time-lapse-enhanced opening credits characterise Canberra as a coldly imposing city hiding dark secrets: the Nishi building is wrapped in mist; high-speed headlights blur along Parkes Way; grey clouds roll over stormy lake waters; and ominous shadows loom across the front of Parliament House.

"Because we were telling a multi-point-of-view story across some quite significant distances we needed to switch back and forth smoothly," Birse says of the show's regular use of scene-setting Canberra images as the action cuts between Broken Hill and the capital.

"There was a clear vision that the connective tissue would be the beauty of Canberra and the intensity of the outback. So the time-lapse moments are not incidental or accidental – there was a mission to create that strong sense of place."

The establishing shot of Canberra in Sunday's opening episode is a spectacular sweeping aerial panorama of the glittering lake, across Commonwealth Avenue Bridge, the National Library and up to the Hill.

The tourism team at VisitCanberra will be delighted.

"So often the thriller elements of the genre immediately call you towards the night but we made a very conscious decision to be doing this in the daytime," Birse explains. "[Director] Shawn Seet had a very clear idea that we wanted to talk about the sense of danger, uncertainty and that discomfort that sits just outside your peripheral vision – those monsters that lurk in the daytime as well as the night."

Already sold to cable TV in the US and broadcasters in other countries, The Code won Birse two Australian Writers' Guild AWGIE Awards earlier this month.

Scripting four of the six episodes herself, Birse's show has been four years in the making. The project began when producers David Taylor and David Maher (makers of House Husbands and Love Child) and Screen Australia offered her "the golden egg" of her own "writer-driven project".

"The big brains in the screen industry are looking more and more to TV and away from feature films because of the capacity to tell really fascinating stories in great detail," she says.

The original seeds for her paranoia-laced plot were "the rumblings of the Arab Spring" and the rise of Julian Assange.

While visiting her partner's family in Israel with her new baby, "the world right outside my window" showed democracy and liberty under threat.

"It felt like Australians were neck deep in world affairs," she recalls. "Access Now, with its strong connections to Australia, were getting stories out of Egypt that would otherwise have never seen the light of day. Plus there was this wider fight for freedom of expression in the digital age.

"What level of control, surveillance, accountability do we have in this new cyber realm? I don't think any of us truly understands what is going on inside that box on our desk. And increasingly we farm out more aspects of our lives into this unknown space that so few of us have a grasp on."

Like US drama Homeland and British spy series Spooks, The Code's sophisticated blend of politics and espionage takes some of its most dramatic cues from ugly truths.

"We dramatically skirt between the what is and the what if," is how Birse puts a grim interrogation sequence in episode two in which a civilian snatched off a Canberra street is later stripped naked, bound with cable ties and a black hood placed over his head as a 1980s pop anthem is used as mental torture.

"We knew from both the original CIA interrogations manual, The Kubark manual, and from more recent revelations about interrogation techniques in the Middle East, that death metal and other aggressive music was used because of their contribution to anxiety and because it was symbolic of the West," Birse says.

"So we had to find our own fantastically annoying earworm song, which was actually kind of fun."

While the genre trappings of The Code's narrative have a topical edge its human heart is the bond between brothers Ned, the journalist, and Jesse, the hacker (played by Dan Spielman and Ashley Zukerman, respectively).

"My natural preset is to write character rather than plot," Birse says. "The political thriller comes with an inherent lit fuse in storytelling terms. Once you light it it tends to run pretty fast and I desperately wanted to humanise the experience because we watch drama in order to engage with emotion not just ideas."

For Canberrans, of course, watching The Code will also be about seeing their home town in a new, and at times murky, light.

"We get to showcase Australia as an grown-up, sophisticated country that is not just blue skies and kangaroos," Birse says. "Yes, we have those. But we also have this incredibly cosmopolitan high-end, high-functioning international city as our capital.

"I think seeing what we have done with Canberra will be eye-opening for a lot of location managers."