Three pregnant women with swine flu are in intensive care in hospital in western Sydney.
The ABC reports another two Australian women gave birth prematurely and one of them is also in intensive care.
The Health Department says the women in intensive care have complicating conditions.
Dr Jeremy McAnulty from NSW Health says the peak of the outbreak is yet to come.
The H1N1 influenza has killed 21 people in Australia so far: 10,387 cases are confirmed.