Mandy Martin was just 26 when she fetched up in the Queanbeyan suburb of Karabar in 1978. She and her then husband, the painter Robert Boynes, were newly married and, with Boynes having taken a plum role at the Canberra School of Art, the pair were hunting for some studio space.

Like many such couples before and since, they had dreams of an acreage, with some kind of barn they might be able to convert. But when the real estate agent suggested they take a look at a brand new house in the developing outskirts of Canberra, they agreed to take a look.

Today, the house they moved into is still there and looks much the same way - a classic blonde-brick suburban double-fronter, with a neat lawn and a quaint '70s pebbled letter box. But it also came with a capacious double garage, a space that seemed ready-made for two working studios.

And Martin got to work, strolling the suburban streets with her cameras, getting to know her neighbours.

More than 40 years later, with a storied and stellar career behind her, Martin began collating a series of her early works to donate to the Canberra Museum and Gallery.

And when senior curator Virginia Rigney first laid eyes on this strange collection of seemingly mismatched works, it took her a while to reconcile what she was seeing with the artist Martin had become.

Martin, who died in July, was one of the leading artists of her generation, best known for her large, bold oil paintings.

Her most famous work, Red Ochre Cove, is familiar to any Australian who has glanced at the news and watched politicians hash it out at Parliament House. The monumental work, measuring 2.8 metres high by 12.1 metres wide, commissioned to be hung in the Main Committee Rooms in time for the building's opening in 1988, was, at the time at least, one of the largest works ever commissioned in Australia.

She described it as as "an Australian coastal landscape set in an industrial timespan", and it was typical of the industrial landscapes and politically charged works that she would be known for throughout most of her long career.

But when Rigney first saw the collection of early works in Martin's studio, she was stymied by how little they resembled the works for which Martin had become known.

Many of the works from Martin's early years in Queanbeyan were delicate, pale and flat portraits of young migrant women in their front gardens. They were sensitive, and strangely intimate, and spoke as much of Martin's engagement and connection to the people around her, as of the subjects themselves.

"She's walking around the streets with a black-and-white camera, and a colour camera, and getting to know the neighbors," Rigney says.

"She'd come from a pretty middle-class background, and then she kind of rejected all of that, you know, as you do in the 70s when you're a young woman of intelligence.

"They [Martin and Boynes] got invited to these neighbours' functions and family gatherings, and she was just really intrigued by these young women who were pretty much exactly the same age as her. They had some of the more migrant backgrounds and some were first generation and what she really became interested in was really seeing them within the context of their suburb."

Martin had come from the heady, emotive environment of community arts, and her work was already politically charged; an even earlier work, from South Australia, is a portrait of a woman, from behind, being restrained by a police officer.

The woman has a rock in her hand, and the canvas is split between two scenes - a chaotic street in which people are tearing down a brick wall, and a fancy cocktail party, at which beautifully dressed guests are observing the woman from a distance. The subject - possibly Martin herself - straddles both scenes.

But here she was in Karabar. She was fascinated by the carefully trimmed lawns, and by the symbolism of the fruit trees covered in plastic - to keep off the frost, of course, but Martin, a South Australian, didn't see this practicality at first.

"From a hardcore feminist perspective, she's sort of railed against the structure of this, and that expectations of women are just going to the suburbs to have babies and so on. So I think she was actually genuinely interested in them as people, and I think you see that in the sensitivity of some of these works, that she's actually really looking at them."

Rigney eventually realised that these early works sowed the seeds for what would be Martin's enduring preoccupation with landscape, and how landscape defines us.

"That's the seed that she makes for the next 50 years of her life, landscape and human response in interaction with landscape," she says.

"The seeds of her whole practice for the rest of her life is really in this work in these suburban backyards of Queanbeyan - I think that's kind of fascinating."

As it happened, before too long Martin became uncomfortable with what she was doing, and worried that she was exploiting her neighbours, or that her images could be seen as voyeuristic.

"Even though she knows them, and that she's taking their photographs, and they're happy for all of that, they're never going to completely understand how their image is being used," Rigney says.

"So she decides right, I'm just going to remove the figure, but I still want to find a way to express human contact within the new environment."

Her attention was then drawn to venetian blinds, windows, angles - surreal vignettes that, while still flat, are less pale, less delicate. She stopped using gouache, and moved to chunky oil sticks on canvas, in a relatively short space of time.

Rigney recalls Martin telling her about a critique she received in those early days from the artist Robert Rooney, himself renowned for his "flat", two-dimensional works, who told her the flatness in her works wasn't working. It was a critique she never forgot.

"The opportunity of this exhibition has been to kind of follow that journey - it's almost like she changes what she's doing every three or four months, and you can see that in this show," Rigney says.

"I think one of the good things about this show for younger artists coming here is about seeing how you can just run with something and keep challenging yourself and keep expanding.

"You can reinvent yourself over and over again."

You can, in other words, experiment with materials, and surfaces and subject matter, with a single, overriding or overlapping theme throughout.

Martin became interested in social and environmental issues during these early years, issues like drought, redundancy, and the Cold War. Her works from this period feature the large concrete water tanks she saw around Canberra and the region.

"She said, 'You know, they're never going to fill', and seeing that imposition in the landscape becomes a real metaphor," Rigney says.

But while the world was filled with existential threats, and politics were heightened, the art world was also interested in painting, and Martin and Boynes travelled constantly. Her works were shown at the Guggenheim in New York, and at the Paris Biennale.

And while Martin's star rose, these early suburban works show the influence of her time in Canberra.

"I think there's something really essentially Canberra about it, even though it's connected to global ideas and concerns," Rigney says.

"You see it in the stark light of those Queanbeyan suburbs, you see the water tanks, you see it in the Queanbeyan School."

Martin's act of donating these works to Canberra Museum and Gallery - a process that became more urgent in the last year of her life when her cancer diagnosis became more definitive - was a way of inserting them into the national conversation.

Writing about Martin after her death, Canberra Times art critic Sasha Grishin said she had adopted a strong feminist and political stance in her work from the very beginning.

"Mandy Martin has always been a socially committed artist whose art was designed not only to appeal to the senses but also to engage the intellect and to stir people into action," he wrote.

"Her art engaged society, spoke of its challenges and addressed the existential threats that it faced."

But her years in Canberra "were a period of search and exploration and ultimately led to national and international success and a very high profile in the visual arts".

"She also became an exceptionally active member of the Canberra arts community, exhibiting widely, engaging in various arts organisations and frequently supporting young emerging artists."

Today her works, especially the early ones from her first years in Canberra, intersect perfectly with Canberra Museum and Gallery's remit as an institution that represents both the region and the nation. They speak to a time when Canberra's art scene was coalescing into something vibrant and resolved, with a rigorous art school discipline that merged into a politically charged era.

And they serve to inspire an incoming cohort of younger artists who, like Martin in the 1970s and 80s, might be grappling with a sense of purpose with their art.

Martin developed a focus, in those years, on the handmade mark - works that showed the physical act of applying paint to the canvas. Today her marks - both the pale watercolour portraits and her dark and vivid concrete tanks - are as powerful and assertive as when she first created them.