AC/DC co-founder Malcolm Young dead at 64

AC/DC co-founder and guitarist Malcolm Young has died at the age of 64. (Getty Images)

Australian rock legend Malcolm Young, a founding member of the band AC/DC, has died aged 64 after a long battle with dementia.

Legendary Australian guitarist and AC/DC co-founder Malcolm Young has died aged 64.

Known for the powerhouse riffs and rhythm guitar that propelled the Sydney group to superstardom, Young had been suffering from dementia for the past three years.

He was replaced by his nephew Stevie for the band's last tour promoting the 2014 album Rock Or Bust.

He died peacefully on Saturday with his family by his bedside, a statement said.

"Renowned for his musical prowess, Malcolm was a songwriter, guitarist, performer, producer and visionary who inspired many," the statement read.

"From the outset, he knew what he wanted to achieve and, along with his younger brother, took to the world stage giving their all at every show. Nothing less would do for their fans."

Formed in Sydney in 1973 by Malcolm and his younger brother Angus, AC/DC built a loyal Australian fanbase on the back of relentless touring and albums such as Powerage and Dirty Deeds Done Dirt Cheap.

From left: AC/DC band members Malcolm Young, Cliff Williams, Angus Young and Brian Johnson.

The band survived the 1980 death of frontman Bon Scott, returning with the classic Back In Black, which remains the second-biggest selling album of all-time with an estimated 50 million copies sold worldwide.

Young last featured on the band's Black Ice tour, which ran from 2008 to 2010 and is the fourth-highest grossing tour of all time.

He is survived by his wife O'Linda and two children.

Angus Young took to AC/DC's Facebook page to share the news.

"As his brother it is hard to express in words what he has meant to me during my life, the bond we had was unique and very special," he posted.

"He leaves behind an enormous legacy that will live on forever.

Contemporaries and those influenced by Young and AC/DC took to social media to pay tribute.

Rage Against the Machine axeman Tom Morello described him as the "#1 greatest rhythm guitarist in the entire history of rock n roll" while KISS frontman Paul Stanley, describing Young as the "driving engine of AC/DC", said it was a "tragic end for a sometimes unsung icon".

Rolling Stones guitarist Ronnie Wood said it was a sad loss.

"Malcolm was a lovely guy and will be really missed," he wrote.

Others sharing their reflections included singer-songwriter Ryan Adams, Boston punk stalwarts Dropkick Murphys and Whitesnake frontman David Coverdale.

Malcolm and Angus' older brother George, who paved the way for his siblings with legendary 1960s group The Easybeats before finding further success as a songwriter and producer with ex-bandmate Harry Vanda, died last month aged 70.