The role of play is being sidelined in England's nurseries because of government shifts towards more formal learning, experts say.
Nursery teachers and other child carers will no longer need training in how children learn through play under two key qualifications being drawn up.
Play is central to learning for under-fives and should feature heavily in the criteria, nursery groups say.
There is no contradiction between teaching and play, the government says.
The Department for Education has been consulting on two new flagship qualifications, the Early Years Educator (EYE) and the Early Years Teacher (EYT), designed to increase the skills of those working with babies and young children. They will be required by nurseries in England from September 2014.
The A-Level-standard EYE qualification says the worker should "deliver children's early education and development from birth to the age of five" and "have an understanding of how children learn and develop".
It also requires them to "deliver effective teaching and learning" enabling children to progress and be ready for school.
While the EYT requires the teacher to have a clear understanding of synthetic phonics in the teaching of reading and appropriate strategies in the teaching of early mathematics, there is no mention of theories underpinning structured play.
The Department for Education said: "There is no contradiction between teaching children and play. Good nurseries do both - education and enjoyment go hand-in-hand."
But the three major bodies representing nurseries, pre-schools and childminders say not mentioning play is a major omission.
Pre-School Learning Alliance chief executive Neil Leitch said: "Learning through play is the cornerstone of good practice in early years because play is how young children learn and make sense of the world.
"The ability of practitioners to support children's play in this way is an essential skill in promoting children's development and should be recognised in these qualifications. We are very disappointed that it is not."
He said the role of the childcare practitioner was to create the right environment for young children to explore and learn in a way which extends their interests at their own pace.
"This is why we have concerns about the top-down pressure from government that could lead to the 'schoolification' of early years as a result of developmentally inappropriate practice such as having young children sit in rows and hold pencils."
'Explore and develop'
He added: "I have this fear that we are moving to a position where we are not wanting our children to be children any more."
There was a growing culture of "rushing children" to a point where they could produce a return for the economy, instead of following academic evidence that learning through structured play and self-development was the best way to prepare children for a successful education, he said.
Purnima Tanuku, chief executive of the National Day Nurseries Association, said "play should be there in every line" of the criteria.
"Children and babies are learning all the time and they are learning through play - even when they go on to schools. You just can't separate it," she said.
While a spokesman for Pacey, the Professional Association for Childcare and Early Years, said: "These qualifications contain no requirement to have an understanding of play theory or practice."
This was of particular concern as the Early Years Foundation Stage (EYFS), the official guidelines on how children under five are cared for and educated, is meant to be based on play, it said.
"Early Years Teachers (EYT) must be required to know that children learn through well-structured play, when they have opportunities to explore and develop their own ideas.
"The expectation that teachers will be able to provide adequately for play, without being given any formal knowledge or understanding during their qualifying years, will only set them up to fail children in their early years, when learning through play is a crucial part of their lives."
And Christine Blower, general secretary of the National Union of Teachers, said: "Play is a fundamental and appropriate part of the early years phase of education and it is therefore disappointing, not to say incomprehensible, that the government has excluded it from their draft framework.
"Structured play is valuable to children in so many ways. Principally, it allows them to develop confidence and enjoy learning new skills. The government should stop sending a message that play does not contribute to child development."
The National College for Teaching and Leadership, which has drawn up the criteria, said educators and teachers would be expected to meet the requirements of the EYFS.
"The EYFS has a requirement for planned, purposeful play and so is already included within the score of the standards and criteria."