Battle of Long Tan still carries scars 60 years on

Singer Little Pattie headed to Vietnam aged just 17 to entertain Australian troops, but wasn't prepared for a mid-show evacuation during the Battle of Long Tan.

Sixty years on from Australia's most costly engagement of the Vietnam War, painful memories remain.

"The battle broke out late in the afternoon," Little Pattie, whose real name is Patricia Amphlett, told AAP.

"There'd been skirmishes beforehand, we were in the middle of a show and we were quickly evacuated safely by jeep and then helicopters.

Of 523 Australians killed in Vietnam, 18 died at Long Tan with another 24 wounded.

Ms Amphlett was back performing at the RSL NSW Vietnam Veterans' Day commemorative service on Tuesday.

In 1966, the teen barely knew where Vietnam was when she ventured off, becoming the youngest Australian performer entertaining the troops.

"I'd been singing for a few years already, and my mum had a call from a government person inviting me to go to Vietnam," the '60s pop idol said.

"The horrible, graphic pictures that ended up being around were later on, so it seemed okay to go, but of course it was a war, a real war."

In the Battle of Long Tan, around 100 Australian soldiers successfully held off thousands of North Vietnamese.

"They were in the mud, it was pouring down with rain, and the spirit of mateship and bravery really came to the fore," RSL NSW President Vincent Walters said.

"I have no hesitation in saying if the battle were to be repeated today, we would see exactly the same spirit."

"It's not just the bravery - it's the camaraderie and cooperation," the 85-year-old said.

Yet when veterans returned home, they were shunned by an Australian population opposed to the war.