Judith Durham's Seekers' bandmates, Athol Guy, Bruce Woodley and Keith Potger, said their lives had been changed forever by losing "Our treasured lifelong friend and shining star".

"Her struggle was intense and heroic, never complaining of her destiny and fully accepting its conclusion. Her magnificent musical legacy Keith, Bruce and I are so blessed to share," Athol Guy said in a statement.

Best known for their unique blend of harmonies and Durham's angelic voice, The Seekers were unlike anything of their time.

They were the trailblazers of Australian music in the 1960s, knocking heavy hitters such as the Beatles off the top of the charts in the UK and taking the US by storm.

From Melbourne cafes to the world stage:

In 1962, an 18-year-old Durham met Athol Guy. He convinced her to sing acoustic folk music in a Melbourne cafe with Keith Potger and Bruce Woodley. They became The Seekers. 

After two years playing in pubs, the band was offered a summer season in the UK — it was "the last thing we expected to happen."

"I had to shock mum and dad and say, 'I'm not actually going to come back'," she said.

The group headed to England, assuming it would be a quick trip.

"Little did we know that our first record, six months later, was going to go to number one all around the world," she said.

"We weren't aiming at being a pop star act, we were a folk group... so that was our niche."

Outselling the Beatles & The Rolling Stones:

The next few years brought worldwide acclaim for The Seekers, with more albums and tours, and a string of hits at a time when they were competing with the likes of The Beatles and The Stones.

"The true perspective that the Seekers were outselling the Beatles, outselling the Rolling Stones... I didn't understand the enormity of that. Now I do," she said in 2016.

The Seekers were the first Australian band to reach number one in the US and the UK, with songs Georgy Girl and I'll Never Find Another You.

Georgy Girl was even nominated for an Academy Award for best original song.

They sold more than 50 million records worldwide and had six top-10 hits during 1965 and 1966.

Durham said she was very self-conscious at the time of the band's greatest success.

"People thought I was hip and cool and people used to emulate my style of dressing, but I used to do it to disguise my weight," she said.

"I didn't realise there were lots and lots of other women going through the same thing. I thought I was the only one."

Despite that success, the band broke up in 1968, having agreed that if anyone wanted to leave, they had to give six months' notice.

Durham wanted to spread her wings and try her hand at opera.

She admitted being nervous about embarking on a solo career, but went on to perform to standing ovations as an international solo artist.

Durham's life after The Seekers:

Personal tragedy was never too far away from Judith Durham.

In 1990, she and her husband Ron Edgeworth were in a car accident — the driver of the other vehicle died at the scene.

Four years later, Edgeworth died of motor neuron disease and Duhram spent many years after that raising awareness about the disease.

In 2013, Judith Durham reunited with The Seekers for a 50th anniversary tour, but it was cut short after she suffered a brain haemorrhage.

She spent six weeks in intensive rehabilitation at a Melbourne hospital before returning to the stage to continue the tour.

Durham said it was a "Miracle" that the musical Georgy Girl, which told the story of The Seekers, made it to the stage in 2015, while she was still alive.

"I'm thrilled to bits that it's happening. It's very special the way it's all done, beautiful production and everything," she said.

"It's not 100% true to life, but that's important for the entertainment value."

She said watching her life on stage was overwhelming in many ways.

"Sometimes I think 'Oh surely, it wasn't that tragic', but everyone says 'Oh my God, what you've gone through'," Durham said.

"It's a funny one, I belittle all the things in my life, I've had a philosophy in life that carries me through those things.

Despite her many years of success, Durham never thought of herself as a pop star, but appreciated the love of her fans.