That hasn't stopped Chris Latham from making the Vietnam Requiem the third in his Flowers of War series of commemorative works, after the Gallipoli Symphony in 2015 and the Diggers' Requiem in 2018. Latham, the Vietnam Requiem's director and musical director, is artist-in-residence at the Australian War Memorial, which commissioned the work to commemorate the 50^th anniversary of the beginning of Australia's staged withdrawal from Vietnam.

"It took 18 months of absolutely solid work," Latham says - organising, researching, interviewing, commissioning and composing.

He had learned and gained confidence from his previous efforts: the Gallipoli Symphony was 10 years in preparation and the Diggers' Requiem took three.

The first half of the concert will contain arrangements of pop songs from and relating to the Vietnam era including We Gotta Get Out of This Place and Bridge Over Troubled Water. Under the direction of jazz musician Bill Risby, performers include theatre and TV star Normie Rowe, who was conscripted at the height of his success as a pop star; singer Little Pattie, who toured in Vietnam to entertain troops; and John Schumann, whose 1983 song I Was Only 19 focused attention on the plight of the war's veterans.

Schumann and Rowe come from different sides of the political spectrum. The former protested against the Vietnam War and regards it as having been "an exercise in futility"; the latter fought in it after being conscripted at the age of 20 and believed in the anticommunist cause, regarding many of the moratorium protesters as believing what "someone else said ... what you see today on social media".

But on two points the musicians agree: the treatment of Vietnam veterans was shameful - a Welcome Home parade did not take place until 1987 - and the Vietnam Requiem is a project worth supporting.

Schumann, 68, says Australia's involvement in Vietnam was "kind of accepted" initially and he "would have been happy to go if called up" but as it wore on and the reasons for it "seemed dubious to say the least", he and many people from all levels of society turned against it. The Vietnam experiences of his brother-in-law Mick Storen and "a sense of fair play and justice" inspired I Was Only 19.

Schumann has long been a supporter of Vietnam veterans and has worked with the Australian War Memorial on other projects and agreed to take part in Latham's project.

Rowe, 74, says he was asked to participate by Little Pattie.

"I got the concept and decided it was something I'd like to do."

He says the work is not intended as celebratory but will help people understand and accept the experience of veterans like himself. He hopes it can be healing.

"There are not many people who see it the way I see it."

Rowe - who says he was told many years later that his call-up had been rigged rather than random in order to draft "an Australian Elvis Presley" - spent three months in a psychiatric ward after his tour with severe PTSD and has spent a lot of time with veterans from Vietnam and more recent conflicts.

The Vietnam Requiem will be the second half of the concert. The work is inspired by but not slavishly wedded to the Catholic Requiem Mass with contributions from several composers including Ross Edwards, Elena Kats-Chernin, Graeme Koehne and Latham himself. It will be directed by Latham with an overture and 12 orchestral movements and choral sections, accompanied by projected imagery, to tell the stories of those involved in and affected by the Vietnam War. These include the Australian and New Zealand battlefield personnel, medical staff, touring entertainers, protesters, journalists and South Vietnamese refugees.

The musical forces will include members of the Canberra Symphony Orchestra, the RAN, Army and RAAF Defence Force Bands and the ANU Chamber Orchestra as well as two choirs, conducted by Toby Cole and Stephen Leek. Soloists will include Slava Grigoryan on guitar and William Barton on didgeridoo.

The texts range widely and include The Beatitudes, translated into Vietnamese and interwoven with a Buddhist Mantra, and a personal account from a war nurse.

Latham says commemorating events such as these has different meanings at different times. The 50th anniversary is for the veterans, he says, the 75th for their families, and the 100th is for reconciliation between countries. But the issues within countries have to be resolved, too.

Latham doesn't think the issues posed by the Vietnam War will be settled easily or quickly.

"It's one of the most unresolved subjects ever seen."

Latham will continue the Flowers of War series. He plans to produce works in 2023 commemorating the Korean War, in 2024 remembering the Holocaust, and in 2025 marking World War II.

The Vietnam Requiem will be on at Llewellyn Hall, ANU, on Saturday June 5 and Sunday June 6 at 1pm. Tickets: $85 adults, $70 veterans and concessions, $25 full-time students. theflowersofwar.org.