The police intelligence analyst, who can only be identified as Sarah for security reasons, was also banned from using morning and afternoon tea breaks because they were "discretionary", reports News.com.au.
According to complaint documents obtained by the Daily telegraph, she was even denied the use of accumulated leave, and her requests for hours that suited her childcare needs were rejected.
She was also told to record the time spent expressing milk at work on her timesheet, and was refused a private room and had to feed her child using either an unlockable and "unclean" interview room, where she was continuously interrupted by police officers, or a toilet cubicle.
Eventually she had no choice but to express milk in her car in the carpark, but because of her "great embarrassment" she drove home and fed the baby.
When she returned she was made to work for the time she had been gone.
The Public Service Association claimed yesterday the woman was one of thousands of new mothers in the public service who were being denied proper facilities for breastfeeding in violation of the Government's own policy.
The Association will launch action in the industrial court today demanding that the Government finally uphold the policy.