Now 99, he's made the trek from Adelaide to the Northern Territory for Friday's annual commemoration of the Japanese attack that killed 240 people.

"For us young blokes, it was very traumatic," Mr Ey told reporters.

"We thought if war is like this, God help us."

The bombing raid at 9.58 am on February 19, 1942, marked the first and biggest attack on northern Australia.

Almost 190 enemy warplanes dropped more bombs on the city than in the assault on Pearl Harbour in Hawaii 10 weeks earlier.

Mr Ey was stationed in the now leafy beachside suburb of Nightcliff, 10 kilometres from Darwin's CBD, when the sky above the harbour started filling with Japanese warplanes.

"When the bombs came through, the trees just blew in the air like matchsticks," Mr Ey's son Len, 73, said, speaking for his now elderly father.

"He said it was horrific. He lost a few mates," Len said.

"He feels it, poor fella."

The bombs didn't discriminate; hundreds of civilians, seafarers and servicemen and women were wounded.

The docks and about 70 wharfies unloading ships were hit, and 11 ships moored in the harbour were sunk.

The bombs also rained down on the-then small town, destroying the post office and killing people taking cover in trenches.

It was the first of more than 200 raids on Darwin, Katherine, Broome, Townsville, Wyndham and Cairns over the next two years by Japanese forces.

NT Chief Minister Michael Gunner said Darwin "was desperately underprepared" for the attacks as he addressed a crowd of about 800 people, including bombing survivors and their families.

Japanese observation aircraft had been spotted above the town in the days before and a ship was attacked near Arnhem Land, he said.

"Everyone knew an attack was coming, yet we had no functioning radar and our service people were stretched in places near and far."

Mr Gunner said the lessons of history were often forgotten, but Darwin would never forget.

"It's not because we glorify war. It's not because we're on the alert. There is no threat ringing in our ears as we go about our daily business," he said.

"But we do know one thing hasn't changed since 1942, Darwin remains the clearest path to attacking the heart and soul of Australia."

Australian Associated Press