Proposed changes to paid parental leave are the mother of all insults, protesting parents say.
Under the Abbott government's scaled-back scheme, due to start in July 2016, new mums will be prevented from accessing both the government scheme and their employer-provided leave.
The government originally painted parents as "double dippers" before retreating from the rhetoric after it sparked a backlash.
Parents would be guaranteed 18 weeks' leave at the minimum wage under the changes, but unions say parents need more.
Expectant mothers, parents, toddlers and nurses gathered at union-organised rallies in Brisbane and Sydney on Monday to voice their disgust over the policy.
"I should not be called a double dipper, I am not a fraud," teacher Anna Uren told a crowd outside federal Treasurer Joe Hockey's electoral office in Sydney.
She said her own experience on her employer's and the government's paid parental schemes had been hugely beneficial for her second child's development.
"I could continue breastfeeding until she was ready to stop and I didn't have to rush back into full-time work while she adjusted to the changed care arrangements," she said.
The World Health Organisation recommends mothers spend 26 weeks with their newborn for exclusive care, breastfeeding and bonding, Queensland Nurses Union midwife and expectant mum Samantha Rae Costa told a crowd of 50 in Brisbane.
"This should be a basic right for all mums - not a privilege reserved for high-income mothers and families," she said.
"Women who currently access both the government's paid parental leave and employer leave are not double dipping, committing fraud or rorting the system."
Angry protesters dumped lemons at the feet of an effigy of Mr Abbott.
Queensland Council of Unions president John Battams said the changes would prevent 80,000 Australian mothers from accessing a government scheme.
"The scheme is an absolute lemon," he said.
