Dignitaries including Prime Minister Julia Gillard, and more than 100 veterans of the bombing, will attend services in Darwin to commemorate the first time the Australian mainland came under attack since European settlement.

The raid was the first and most destructive of 64 attacks on Darwin between February 1942 and November 1943.

Australian War Memorial military history expert Karl James said it was a defining event in national history because it was the moment the war had come to Australia's doorstep. Previously, the devastation of World War II was fought in Europe, the Middle East and North Africa.

But within two months of their stunning victory at Pearl Harbour, the Japanese had swooped through south-east Asia, captured Singapore and then four days later sprung a surprise attack on an unsuspecting Darwin. The air raid came in two waves, with about 230 enemy aircraft dropping more bombs on the Northern Territory capital than on Pearl Harbour.

At least 243 people were killed, 400 injured, and 20 military aircraft and eight ships destroyed.

Most of the dead were United States servicemen aboard the USS Peary, suffering 88 killed and 13 wounded.

Dr James said the infamous assault forged the still strong military alliance between Australia and the United States.

''Australian and American forces go all the way back to World War I, so there was a history but they really married in many ways in Darwin,'' Dr James said.

Those links are on show today with the presence of US ambassador Jeffrey Bleich and the USS Chafee in Darwin for the anniversary. The commemoration will begin with the sounding of an air-raid siren at 9.58am, the time it belatedly sounded on the same day 70 years ago.

Forty seconds later an RAAF flyover of the city will represent the first of the two attacks that occurred that day, with Darwin High School year 12 student Shelley Bryant ending the ceremony with a recital of the Ode Of Remembrance.

The Chafee crew will take on young Aboriginal men in an AFL match later in the day. Last night, the Prime Minister, and Opposition Leader Tony Abbott, attended a commemorative ball.

Governor-General Quentin Bryce yesterday opened the Defence of Darwin Experience, an interactive display that tells dozens of the stories of February 19, 1942 and the months that followed. with AAP