The SMH explains it as expecting 50 and getting 3000 triumphant celebrators.

"But up to 3000 visitors have arrived this week in the nearby town of Vung Tau for a series of events, including a gala dinner Thursday evening at the five-star Pullman Hotel, according to Australian businessmen in the town. They have packed the town's bars and restaurants."

More figures:
The major Japanese bombing of Darwin killed about 140 Australians with around 100 Allied deaths. In total Japan's bombing of Aust killed about 900 in 1942-3 and lost 131 bombers and fighters.
Thus Japan's casualties here were about the same as Oz in Long Tan.

As someone who spent a bit of time in Cambodia, Laos and North and South Vietnam in the late '60s
I am quite happy to celebrate(?) our worst overall defeat, thanks to the stupidity of the Americans and
their leaders as cited by Paul1405.,here at home.
I prefer to sit on my porch and look out over the property I was told I was defending for the future of our kids (more lies)
What the boys of Long Tan achieved was miraculous in itself but not unexpected as Australians and it is
crap that medals and citations are just now starting to flow.
For the Communist North Vietnam government of which, I am sure their are remnants of their Army still
in power, the 11th. hour rebuttal is just another shock tactic in their still running war chest with the west and Australia.
Walk away tall and proud soldiers of D company,6RAR

You are OK with Japanese uniforms, music and troop entertainment for 3000 soldiers of the Emperor in Darwin in these days?

Is it all that difficult to fathom why the Vietnamese might still be somewhat sensitive with matters concerning a war which lasted for 30 years on their home soil, and resulted in the destruction of their country, with over a million of their citizens killed, many of whom were civilians. No celebrations on our part are necessary, rightfully they should be seen as offensive, Save our respect for those killed in all wars for ANZAC Day.

What is needed is a concerted effort by the relatives and supporters of interned Japanese World War 2 prisoners to ask [demand] the Oz govt and RSL facilitate preferential treatment/diplomatic courtesy to allow them to hold large memorial services for the Cowra Japanese POW escape whenever they want to - shock, horror! - I am Australian born of an Australian serviceman [died in New Guinea] and English born mother [both deceased]! The sooner the Great Anzac Spirit and how our brave lads died for their country [and not Yanks paranoid about Communism] in Vietnam is dead and buried the better - Most of the wars fought are self vested interests where both sides try hard to paint the picture that REALLY the Queen, the Emperor, The President, is a more deserving than the other side's head honcho or it is clearly 'In the National Interest' [of 'us lot' and not 'them lot' and dehumanise like the Jews labelled as rats by Nazis and the Viet Cong ad Gooks] The Poms Hallowed Old battle hymn "Land of hope and glory, mother of the free" is not challenged as rubbish still today. Great Britain basically took over half of the world and insisted the ignorant locals were wrong to be free from 'superior' British civilisation and r-e-a-l-l-y the king or queen or the military and politicians were acting in the newly ruled over local peoples' national interest by encouraging them with Christian firepower to agree that the Poms really knew best and that had a 'righter right' to rule over the locals! If, as a Turkish mother in Australia I wish to have myself or my relatives stand in for my son killed at Gallipoli by the invading Anzacs to Turkey in 1918 at 25 April memorial services, etc in Canberra or Sydney, et al cities do you seriously think that this would get a big govt and RSL tick of approval and a respectful friendly hearty slap on the back and "Good on ya Luv, mate' ? Anzac Self interest Reigns Supreme! "We alone know what is right!"