"I am anti-authoritarian to my marrow," Shriver says. She ignores red lights on her bicycle, fudges expenses on her tax return and regularly gets into rows with bureaucrats. In her novels, she prods and pokes and picks at complacent bourgeois assumptions, including her own. Received wisdom is a balloon to be pricked.

Her latest book, The Mandibles, is set in a near future United States of America in which the government has defaulted on its debts, the US dollar has been usurped by a rival international currency and the stock market has crashed, wiping out fortunes. Soldiers raid houses to confiscate gold, cabbages costs $20 a head and a shower lasting longer than four minutes is an impossible luxury.

Shriver presents two dystopias: an imploding society in which money is worthless and behavioural norms no longer apply and the terrifying totalitarian taxation state that follows. The alternative is a hard-scrabble libertarian republic with few laws to break, little tax to pay, no red tape and no safety net. It's no utopia but it is closer to her anti-authoritarian heart.

In her imagined US, rampant political correctness mean people now dial 1 for Spanish and 2 for English. The country's first Latino President, Dante Alvarado, conducts press conferences in his native language. Although she is adamant The Mandibles "is not exclusively an attack on liberal America," Shriver enjoys ridiculing left-wing cant and does so expertly.

"I think my fears are widely shared," she says, without fear of contradiction. Conservatives have been warning about inflation and out of control Social Security spending for decades. The Mandibles is a Fox News fever dream about what could happen if the government keeps running up colossal debts and printing more money at the first sign of trouble.

"Most novels are written by people of an identical political persuasion in this country," she observes. "I'm actually only one of the only voices of departure in the entire literary community. So if I don't at least introduce a political note that clashes or offers a counterpoint to the prevailing shibboleths, then who's going to? It's like my job."

Her summer house (she and her husband, jazz drummer Jeff Williams, live in London nine months of the year) is on a pleasant cul-de-sac in flat white-drinking, Obama-voting, John Maynard Keynes-believing Brooklyn. She's more likely to bump into another novelist running laps around Prospect Park than someone else who shares her views on the welfare state, which tend towards libertarianism.

Last November, in neighbouring Park Slope, activists gave out mock summonses to all the affluent white people riding their bikes on the pavement to make the point that in poor, black communities, people are much more likely to be ticketed for minor offences. Breaking the law is a luxury, the ability to do so unevenly distributed.

"I do not obey rules because they are rules, but because they make sense. When they don't, I feel free to ignore them – although I am as prey as anyone to shit-eating terror, and if the consequences of being a scofflaw​ are too dire I'll toady along with the best of them," Shriver says.

Shriver had written seven novels, six of them published, before finally finding success with her eighth. We Need to Talk About Kevin described the relationship between a troubled child and his ambivalent mother, and asked whether she should be blamed for his psychosis. It won the Orange Prize for fiction, was adapted into a hit movie and made Shriver rich after more than a decade of striving. She chose not to have children herself.

"I have a tendency to be a little nostalgic about being a failure," she says, pointing out that in the 12 years that she worked as a reporter in Belfast and wrote novels in her spare time, she was never interrupted by interviews or tours or literary galas, because so few people bought her books.

She is drawn to controversial, uncomfortable subjects – the more provocative the better. So Much for That examined the disastrous consequences of for-profit healthcare in the US. Big Brother tackled obesity. In Game Control, a character proposes murdering 2 billion people as a solution to overcrowding and scarce resources. "I like to craft characters who are hard to love," Shriver once told Bomb magazine.

This appears to include her own persona. At 15, she changed her name from Margaret Ann to the traditionally masculine Lionel. In interviews and photographs, she sometimes plays along with the notion that she is stern. I found her to be charming, but smart, opinionated women often acquire a reputation for being intimidating, whether they deserve it or not. I suspect she quite enjoys it.

"I'm always talking to journalists who have formed some preconception of me as 'scary' – which I find absurd," she says. "I don't think I'm very difficult to talk to… I don't think I'm harsh, in person, and mean to people. I sure hope I'm not. It is never my intention."

Shriver has written herself into The Mandibles, in the form of Nollie, an expatriate American author in her mid-70s, living in France off the proceeds of her one hit novel. Although the line between public image and self-image, between self-parody and self-congratulation, is a tricky tightrope for any author to walk, she clearly had fun up on the wire.

Nollie gets bad reviews and publishes books that no one reads. She is "wildly opinionated" and fanatical about her jumping jacks. Shriver, an extremely sporty 58, does the interview dressed for her afternoon tennis match, in hot pink running shorts and a blue T-shirt.

Nollie has given up writing, citing book piracy and diminishing financial returns. She arrives at the house that will soon be home to the whole Mandible clan laden with crates of her novels, and is persuaded by her teenaged grand-nephew Willing, who understands the gravity of the financial crisis long before any of the adults do, to burn them for heat.

"The whole character's supposed to be a wink and a nod to the reader," Shriver says. Nollie is an anagram of Lionel. The names of the books tossed into the oil drum – Better Late Than, Virtual Family, The Stringer, Cradle to Grave – are all working titles Shriver abandoned.

"I had originally intended to take the mickey out of myself, and I hope I successfully did so – mercilessly, in some instances. The thing is, I grew rather fond of her. She became an independent character and not just a caricature of me."

Nollie turns out to be the one Mandible with any tangible, portable assets. Towards the end of the novel, she reminds Willing that she came about them the hard way. "I earned it," she tells him. "By staying up late at a keyboard when my friends were carousing in bars. By reading the same manuscript so many times… that I came to hate the sight of my own sentences. By appearing in public events and saying the same thing over and over again until I was senseless with self-hatred." I put it to Shriver that this is nakedly her own voice. Fair comment, she says.

Consistently challenging conventional wisdom requires supreme self-confidence. It also takes discipline, to avoid crossing a line into provocation and contrariness for its own sake. Reading The Mandibles, I often wondered how much of Shriver's mockery of middle-class platitudes is heartfelt, and how much stems from her desire to provoke, to be deviant, to break a rule a day.

When I ask if she gets into rows at dinner parties, she answers "yeah, I do" instantly. "And the thing is that I like arguing, as long as it's good-natured. I don't like getting into arguments where it gets very personal. I had an argument about Brexit shortly before I left London, and she just went crazy."

I say I bet you were arguing that Britain should leave the European Union – a contrarian position in upper middle-class London. "Right. And she went crazy. The only thing that was interesting about it was watching somebody lose it and wondering whether I get that way. It was like 'note to self: don't do that. This is not effective. Keep your cool.'"

Nollie never loses her cool. I doubt Shriver does either. It takes some nerve to describe oneself as a "mischievous, scandalising provocateur" in print, but she has earned that right, too.

Lionel Shriver will appear at the Festival of Dangerous Ideas at Sydney Opera House on September 3 and at the Melbourne Writers Festival on September 4.