Three Australian warships were challenged by the Chinese military as they travelled through the disputed South China Sea earlier this month.
The confrontations with the People's Liberation Army are believed to have occurred as China was conducting its largest ever naval exercises in the hotly contested waters.
Defence sources confirmed HMAS Anzac, HMAS Toowoomba and HMAS Success were challenged by the PLA Navy as they were transiting towards Vietnam where they are now conducting a three-day goodwill visit in Ho Chi Minh City.
One official, speaking on the condition of anonymity, insisted the exchanges with the Chinese were polite, but "robust".
The Defence Department refused to answer questions or discuss details of the interactions between the Australian warships and the Chinese military.
In a statement it confirmed the ships travelled through the South China Sea.
"The Australian Defence Force has maintained a robust program of international engagement with countries in and around the South China Sea for decades," it said.
"As they have done for many decades, Australian vessels and aircraft will continue to exercise rights under international law to freedom of navigation and overflight, including in the South China Sea."
Earlier this month, Beijing boasted of the largest-ever military exercises by the Chinese navy in the contested region. China brought much of its naval hardware for the world to see - 10,000 personnel, 76 fighter jets, 48 naval vessels, a nuclear powered submarine and China's first aircraft carrier.