The soldiers of Delta Company - 105 members of the 6th Royal Australian Regiment - plus a three-man New Zealand artillery forward observer team, could hear music.

Col Joye and the Joy Boys and 17-year-old Little Pattie (Patricia Amphlett), had been flown in to the Australian Task Force base at Nui Dat, 35 kilometres east of Saigon, to entertain the troops.

The sound of their concert, on a makeshift outdoor stage, carried east, out towards a village called Long Tan, where D Company had been sent to patrol for signs of the enemy.

An Australian Army officer and former journalist, Major Ross Smith, was in charge of public relations at the Nui Dat base, and would monitor the entire day. The only other journalist at Nui Dat was Geoff Murray, of AAP-Reuters.

It was August 18, 1966.

Smith and Murray would thus have the job of reporting what has since become emblematic of courage against overwhelming odds: the Battle of Long Tan.

Eighteen Australians were killed in the battle in a rubber plantation, one of the deadliest days for Australia during the whole Vietnam War.

The real victory was that so many survived and held despite being outnumbered by Viet Cong and North Vietnamese forces by at least 10 to one, and possibly 25 to one.

By the end of the day, Smith decided Murray's reports, and not that of the army, would inform Australians of the battle of Long Tan.

"I decided as he was the only journo on base, I would not file a story back to army HQ as I felt we would be competing with each other and I wanted him to get the credit," Smith recalled in a speech to the RACV Club in Melbourne on Friday to commemorate the 53rd anniversary of the Battle of Long Tan.

"Naturally, I got a big rocket from Canberra the next day for not filing but I had the satisfaction of knowing that Geoff's story had got into all the media that took AAP-Reuters back in Australia."

The action began 24 hours before the major battle.

"Early the previous day," said Smith, now 81, of Inverloch, "the base had been shaken, without warning, by enemy mortar and recoilless rifle fire, resulting in 24 soldiers being wounded. This raised fears that it could be a prelude to a full-scale enemy attack on the base ...

"No attack followed, however. But there remained a heightened air of expectancy."

That expectancy was soon to be met with fierce reality.

"At about 3pm, heavy monsoon downpours began in earnest as D Company, under Major Harry Smith, had their first contact with soldiers dressed in fatigue uniforms similar to Australian dress, and armed with AK7 Russian assault rifles. This indicated a main force Viet Cong formation.

"So began Australia's four hours of hell in Vietnam."

The music was over.

"As D Company locked horns with the main [VC] force 274 Regiment, it was quickly decided by Task Force Commander Brigadier David Jackson that the concert party should be flown out of the base by the RAAF. But I do remember one of them, Col Joye, was left behind.

"He was given captain's pips on one shoulder and flight lieutenant's flashes on the other and placed in the padre's tent."

Meanwhile, the "contact" in a rubber plantation about five kilometres east quickly escalated into a major battle, with the Australians and New Zealanders pinned down and attacked by waves of Viet Cong.

The Viet Cong commanders used bugle calls to direct their fighters, a sound Smith said anyone associated with Long Tan would remember for the rest of their lives, along with the constant noise of exploding artillery.

"Throughout the whole of hostilities, the enemy directed its movements by the sound of bugles and their soldiers strictly obeyed these orders even if it meant sacrificing their own lives to obey the call of the bugle.

"And they were massing for attack with large volumes of fire. The three platoons -10, 11 and 12 of D Company - were now fighting off heavy enemy attacks and manoeuvring to counter enemy flanking movements.

"Within 20 minutes the No.11 Platoon Commander, Second Lieutenant Gordon Sharp, a National Service Officer, and a third of his platoon of 28 men had been killed or wounded. The survivors were forced to pull back and rejoin the other two platoons.

"They were manoeuvring to counter enemy flanking movements under heavy fire and blinding rain."

The besieged Anzac called desperately for artillery fire.

"Soldiers went to ground and withstood repeated enemy attacks, including massed human wave assaults," Smith said.

"But the artillery was magnificent and it was carefully brought in as close as it could be for safety reasons, onto the never-ending surge of enemy forces.

"At times, the fire of all 18 guns totalled over 100 rounds a minute from the Australian and New Zealand Artillery Regiment at Nui Dat, only five kilometres away."

Ignoring the furious arguments of senior staff at Nui Dat, two RAAF helicopter pilots, aware D Company was running out of ammunition, risked everything to take off at 6pm and to hover at tree-top level above the battle, dropping ammunition boxes wrapped in blankets.

Finally, at 6.45pm, seven armoured personnel carriers with soldiers of 6RAR (Royal Australian Regiment) and elements of 5RAR infantry aboard arrived to relieve the surviving Australians and New Zealanders.

The small force had withstood waves of attacks from an estimated 2500 Viet Cong and North Vietnamese Army regulars.

Seventeen Australians from D Company died on the battlefield, a trooper from the Armoured Personnel Carrier force died from his wounds some days later, and 24 members of D Company were wounded.

The official death toll of North Vietnamese Army and VC was set at 245, but the number is widely believed to be higher.

"And what of Col Joye?" said Ross Smith. "I met him as I came out of the Ops Room the morning after ... and he was naturally overjoyed.

"I walked him down to Luscombe Field and put him on an aircraft for Saigon and have not set eyes on him again except on TV."