Is this Australia's best wellness retreat?

Under a black velvet sky, spotlit with stars as brilliant as diamonds, a nightly musical is being performed. It involves a repetitive chorus from a choir of loquacious frogs, overdubbed by otherworldly duets of night birds, with the occasional eerie contribution from a lone peacock.

We are just 20 kilometres from the seafront high-rises and busy shopping malls of Broadbeach, but on this lush plateau on the land of the Yugambeh people, it may as well be 2000. Set among old-growth forest remnants in the Gold Coast hinterland, Gwinganna Lifestyle Retreat is part-owned by actors Hugh Jackman and Deborra-Lee Furness, and has played host to high-profile guests like Nicole Kidman and Keith Urban, Naomi Watts and Joel Edgerton. The retreat turns 17 this year, but continues to innovate and collect accolades; most recently World's Best Eco Spa 2022 in the World Spa Awards.

I'm here for a five-day "optimal health" retreat - a much-needed reset for 2023 after a year of both excess and lack - too much food, wine and stress, and not enough exercise, sleep or mindful living.

The retreat consists of re-purposed or relocated cottages, suites, villas, and pavilions, spread out among towering eucalypts and semi-tropical gardens. There are two rainwater pools, a tennis court, gym, infra-red sauna and wellness centre, spa and yoga studio.

I'm dropped by golf buggy at my accommodation, which has two queen beds, a small sitting area and a deep freestanding bathtub on a veranda overlooking nascent orchards and lawn, where pretty-faced wallabies loll about like 1980s Cleo magazine "man of the month" centrefolds.

Days at Gwinganna begin with a qigong session on the lawn. For someone with no coordination, group activities are usually a trial, but this is slow and easy, focusing more on the breath than complex movements. After qigong there are guided walks - one easy and one more challenging, along one of the tracks that crisscross the retreat's 200 largely untamed hectares. There is no obligation to do anything at all, however, as per a mysterious man who only ever appears for a swim each morning while everyone else is eating breakfast.

Instead of tapering off coffee as suggested, I just go cold turkey and develop a mild detox headache by the second day, but the food, imaginative and generous, offers a welcome distraction. Everything is organic, sourced from local farms, or the property's own gardens - dairy-free and gluten-free, carefully designed to aid digestion and balance blood sugar, detox sluggish livers; anti-inflammatory and gut-friendly - although you'd never know it.

Our assigned tables at meals change daily and over five days, I meet people from all walks of life: a cage fighter and a central Queensland cattle farmer, an Oscar winner, a lawyer, and a pair of teachers about to set off on an extended world adventure.

"Wired but tired, is how a lot of people arrive at Gwinganna," says naturopath Shannon McNeill. She's one of the speakers at the daily seminars, delivering talks on topics such as sleep, stress, the gut and movement.

After breakfast it's a "yin" or "yang" activity - a choice of something high-intensity such as boxing, or more chilled, like yoga or meditation. It's the spa, however, the largest in the southern hemisphere, built around a hexagonal tropical courtyard, that proves the strongest draw. Almost every guest ends up here some time, wrapped in a robe, sipping herbal tea as they wait to be fetched by their therapist or stripping down to swimwear and sweating out toxins in the Turkish-bath-like crystal steam room.

There are 60 therapists with more than 80 treatments on offer. I have an intensive hydration facial, a Thai-style massage and spend time in the "wellness room", where high-tech equipment includes LED light therapy, an infrared sauna, oxygen and meditation chair, massage chair and a Somadome "meditation pod". One of only two in Australia, it uses colour therapy plus a soothing voice over binaural beats to put you into a deep state of relaxation, with different programs designed to change mindsets - in my case, I choose one that will convince my subconscious to halt its constant self-criticism. I also put aside my cynicism and have my chakras realigned with a vibrational energy healing session, falling into a deep meditative state and coming out of it with tingling hands and a feeling of warmth between my shoulder blades.

A good deal of my time at Gwinganna is spent preternaturally relaxed, humming in my head as I walk among the trees at the retreat. I exercise with more pleasure than I have for ages, let go of self-consciousness and overshare with strangers, and - despite the noisy nocturnal soundscape - sleep more deeply than I have for a year.

On our final night we're encouraged to commit to paper the things we wish to get rid of in our lives and throw it onto the fire. My old head-voice starts to sneer, but I hush it and write my list, throw it in the flames and watch it burn with satisfaction. And with that, I become a tabula rasa, fired up to experience a new, different story in 2023.

Natascha Mirosch was a guest of Gwinganna Lifestyle Retreat.