The campaign group, Fair Funding for Our Kids, is demanding Glasgow City Council rethinks its strategy when it comes to buying places for youngsters in private nurseries.
Parents also say the local authority is breaking the law by not providing them with five free sessions a week, which applies to children over the age of three.
They are frustrated that many private nurseries in Glasgow have had funding removed, and say there are not enough spaces in council-run facilities.
Initially started by parents from Clarence House nursery, in Maryhill, the group has joined forces with others who are in the same situation. Seonaid Daly, from Finnieston, whose daughter goes to a Yorkhill nursery, said the options for working parents were limited.
The 32-year-old said: "The few that do offer this service still seem to prioritise parents seeking part-time places and those who have social needs.
A council spokeswoman said there had been no reduction in the number of places and said the local authority had even over-purchased places in the city centre.