Some wrongly see the new curriculum as a return to a "hippy" 1960s-style education in which children are allowed to roam free, said one headteacher.
Academics evaluating the first year of the foundation pilot uncovered a worrying lack of knowledge about the curriculum among parents, despite the efforts of many schools and pre-school groups to keep them informed.
In a report to the Assembly government, published this week, they recommend a high-profile national media campaign to bring parents and the general public up to speed before the curriculum is rolled out nationally from 2008.
But Margaret Morrissey, from the National Confederation of Parent Teacher Associations, said parents had reached saturation point. "Busy parents are fed up with having to keep up with complex new policy that is best left to professionals."
The findings suggest little has changed since a TES Cymru survey nearly two years ago which found that fewer than two in five parents supported plans for the foundation phase, in which formal lessons may not start until children are seven.
However, the pilot scheme is proving overwhelmingly popular with school heads, early-years staff and pre-school playgroups, according to this week's evaluation report.
It confirms previously published findings that children do better in pilot settings with qualified teachers - even if there are more children per adult.
And there is overwhelming support for the 8:1 child to adult ratio being piloted for under-fives, with participants claiming that smaller groups have made a real difference to learning opportunities and classroom management. The research team said there was not yet evidence to determine whether standards had changed.
However, teachers are divided over plans for larger teaching groups for older children of 13:1 for five to seven-year-olds.
The report says adequate resources, training, guidance, assessment and curriculum materials need to be in place before the delayed national roll-out begins in 2008, in order not to "compromise children's learning".
Gail Rees, acting head at Troedyrhiw infants school in Merthyr Tydfil, one of the pilots, said parents were often turned off by the idea of "play" in a school setting.
She said: "They seem to think being free to roam and explore is a return to the hippy culture of the 60s - flower power and all that.
"But when we explain more about the strategy they see there is not so much freedom after all, and children are simply lured into learning because they want to."
Parents at another pilot school, Mount Airey infants in Haverfordwest, Pembrokeshire, have been able to attend workshops on the foundation phase, and leaflets are also being sent home explaining more about the aims of the strategy.
Children have been making mud pies and going for walks in the rain - something parents are not always happy about, according to head Sally Francis.
She said: "I am nearing retirement and I have seen it all. However I can honestly say I love the foundation phase.
"My pilot year is so advanced that the teachers have to plan every night to keep up with them. It's great to see children enjoying the outdoors."
Monitoring and evaluation of the effective implementation of the foundation phase (MEEIFP) project across Wales, Iram Siraj-Blatchford et al, www.learning.wales.gov.uk