Mum-of-three Belinda Evans, from Colville in the north of the Coromandel Peninsula, says she has no option but to send her 4-year-old son to the local preschool.
"If we didn't use the local facilities I would have a 30-minute drive to the next childcare centre, so shopping around simply isn't on. Fortunately, I only have to pay an optional charge of $10 every month to cover things like popcorn or other treats."
Rebecca Schwass, from Te Puke, says she is lucky to get free childcare for her son at a local Barnardos kindy.
"Comments about shopping around don't make sense for people in small or out-of-the-way communities," she says. "It is not like we live in the middle of Wellington or Auckland where it might be a lot easier to pick and choose."
About 91 per cent of preschools have signed up to the 20 hours scheme, launched by Labour as "20 hours free" in 2007. National quietly dropped the word "free" in 2009, but centres are still prohibited from charging.
Parata said: "Parents must not be charged for 20 hours (at centres). The Ministry of Education investigates all alleged breaches of funding."
Our survey found some centres aren't giving parents a choice, and "optional" charges - for costs such as lunches, extra staffing, sunblock - are often compulsory.
Education Ministry ECE group manager Karl Le Quesne urged parents being forced to pay optional charges to contact the ministry. "Parents can't be required to pay that and if a service is requiring parents to pay that then we want to know."
However, the ministry did not interfere with centres requiring children to be enrolled for a minimum number of hours.
Labour spokeswoman Sue Moroney said the rules needed tightening. Many providers were making up for the squeeze on funding but some were focusing on profits.