 However , with the war approaching a stalemate strategically , the Australians were substantially reinforced following the trend of further American troop increases , with a third infantry battalion arriving in December , while a squadron of Centurion tanks and additional Iroquois helicopters were added in early 1968 . Total Australian strength in Vietnam grew to over 8 @,@ 000 men , its highest level during the war , effectively doubling the combat power available to the task force commander . Likewise , American military strength in Vietnam had risen to 486 @,@ 000 men while South Vietnamese forces had expanded to 643 @,@ 000 by the end of the year . In spite of this build up North Vietnamese strength in South Vietnam also increased growing to 278 @,@ 000 men , and although communist strategy remained fundamentally one of protracted war , preparations for a strategic offensive had reached an advanced stage . <unk> in the Tet Offensive in early 1968 , the offensive would aim to provoke a popular general uprising among the South Vietnamese people against the government and its American supporters and would take the form of a massive simultaneous surprise attack on population centres throughout South Vietnam . 1 ATF would be heavily involved in the fighting during Tet , deploying astride communist lines of communication in support of American and South Vietnamese forces defending the Long Binh @-@ Bien Hoa complex north @-@ east of Saigon during Operation Coburg , while also repelling repeated Viet Cong attacks against Ba Ria and Long Dien in Phuoc Tuy province . 
