From January 1, single parents have not been eligible for the Parenting payment once their youngest child has turned eight years old and have been transferred to the lower Newstart allowance.
More than 60,000 single parents now receive between $60 to $100 a week less under entitlement changes.
The single parents action group (SPAG) are organising rallies in all major cities on February 5 to push for the government to reverse its decision, with the main protest at Parliament House in Canberra.
Protest organiser Samantha Seymour said the payment changes would have a detrimental impact on single parent families.
"Our purpose is to show the government that we will not tolerate their decision to further deprive and isolate Australians whose only crime is being single parents," Ms Seymour said in a statement on Sunday.
Families spokeswoman for the Australian Greens, Rachel Siewert, said she was concerned about the long-term impact of the lower Newstart payments on parents and their children.
"We shouldn't be condemning people to poverty," Senator Siewert said in a statement.
She said the government should reverse these payment cuts and also boost the Newstart allowance by $50 a week.
The government introduced the changes, worth around $728 million in savings over four years, in its bid for a budget surplus in 2012/13.
Last December, Treasurer Wayne Swan said the government was unlikely to have a surplus this financial year due to lower than forecast tax revenue.