In a different venue, a church bell ringing would have signalled the start of another AC/DC hit. With Brian Johnson up front and Angus Young in his trademark school uniform on lead guitar, the band would have launched into Hell's Bells as fans rocked along in Paris or Philadelphia, London or Las Vegas, Munich or Melbourne.

But in Sydney's St Mary's Cathedral on a muggy Tuesday morning, the church bells were a sombre touch during the funeral for Malcolm Young, the master rhythm guitarist, songwriter and guiding force for one of the world's great rock bands whose death at the age of 64 prompted tributes from musicians and fans around the world.

The private service attended by more than 1000 people including brother Angus, Johnson, long-time drummer Phil Rudd, Jimmy Barnes, Angry Anderson, Rick and John Brewster from The Angels and promoter Michael Chugg, saw Young remembered as a humble man who never forgot his working-class origins despite his success.

For wife O'Linda and children Cara and Ross, there was a reminder of Young at his blazing best in a poster on the altar that showed him playing guitar, long hair cascading over a singlet. His famous Gretsch guitar, nicknamed "The Beast", was on his coffin. For the congregation, there was a souvenir guitar pick labelled "M⚡Y" in the program.

Angus Young carries a guitar as he watches brother Malcolm's casket carried to a hearse outside St Mary's Cathedral on Tuesday. AAP

Monsignor Tony Doherty, who admitted taking a crash course in AC/DC's music before leading the service, described Young as "an extraordinary Australian and an extraordinary musician".

He recalled Young's sad final stage in a nursing home after being diagnosed with dementia.

"This genius of music and song had been cruelly struck silent," he said. "Sitting in his room with ... one of the best rhythm guitarists in the world, his beloved Gretsch guitar on the wall and an electric piano, it was a truly distressing moment.

"But somehow there was still life, vitality and great love."

Jimmy Barnes was among the mourners at Malcolm Young's funeral at St Mary's Cathedral. AAP

In a eulogy, nephew Bradley Horsburgh said Young could not have been further from the stereotypical rock star.

"To those who knew him, he was gentle and humble," he said.

The Scots College pipes and drums band leads the funeral procession outside St Mary's Cathedral. Janie Barrett

"Above all for Malcolm came family. Even in his later years, the smile on his face at family gatherings said it all.

"He loved spending time with his siblings, wife, children, grandchildren and extended family."

An AC/DC fan sits outside the funeral. AAP

Young would spend New Year's Eves making sure everyone gathered at the highest point of his Balmain house could see the Sydney Harbour fireworks while he stood up the back, just as he did on stage. He loved football but was a disaster around water.

"He was famous for rhythm but infamous for boating skills," Horsburgh said.

AC/DC frontman Brian Johnson. AAP

Always happy to be out of the spotlight, Young enjoyed the simple pleasures of a family trip to Kangaroo Valley and "a rare shopping outing to Gowings where Mal was very pleased to walk out with two pairs of jeans and half a dozen black t-shirts."

David Albert, representing the band's long-time label, said their success included selling more than 200 million albums and having their songs streamed almost a billion times, with Back In Black the second highest-selling album of all time.

A guitar pick inside the order of service program for Malcolm Young's funeral. AAP

He described Young as "quiet, humble [and] understated" as well as a rock legend.

As the casket was carried from the cathedral, someone up the back applauded - force of habit, no doubt - while others teared up as a pipe band played Waltzing Matilda.

The order of service program from Malcolm Young's funeral in Sydney. Janie Barrett

Having lost two brothers in three weeks - George Young, the former Easybeats guitarist, songwriter and AC/DC producer then Malcolm - Angus looked understandably shaken as left carrying Malcolm's guitar.

It was a service without a note of AC/DC music. No Thunderstruck or Back In Black. No TNT or Dirty Deeds Done Dirt Cheap. Just a boy's choir singing Amazing Grace and The Lord Is My Shepherd.

But as the hearse moved off down College Street, the pipe band went with a few bars of It's A Long Way To The Top then segued back to Waltzing Matilda.

A touching exit for an Australian music legend.