In a report, the school inspection service Ofsted, says that some nursery teachers are relying too heavily on formal teaching and are not doing enough to encourage "free play".

Some pupils, the inspectors say, have not been given sufficient opportunity to "try out a range of tools". A further criticism is that "sand, water, paint, dough and clay" are not "freely accessible".

The criticism has been rejected by some teachers and parents, however, who claim that the criteria used by Ofsted represent the "lowest common denominator".

They fear that the effect is to penalise nurseries that have moved beyond teaching children how to speak or how to hold a knife and fork.

Jean Brown, the owner of Glenfield nursery school, in Stockton-on-Tees, one of those that have been criticised, said that she believed that the "free play" approach could threatened high standards.

Her private nursery, which has 76 children, received glowing reports until the new criteria were introduced, but in the most recent inspection its staff were criticised for "leading" children's activities and giving children "few opportunities to explore feelings and thoughts".

Mrs Brown, a qualified teacher who has run nurseries for 30 years, said: "Inspectors seem to have an entirely different attitude now. They have had as little as 10 days training and if the nurseries system does not fit into their little tick boxes, they don't like it.

"The new criteria say that children should be able to count to 10. Our children can count well beyond that. They know their shapes and colours and can write their names. They are socialised and can communicate so we can move on to other things.

"On one hand the report said our older children were 'very confident and independent' and yet it also said we didn't give them enough opportunities to `select resources independently'. The criteria represent the lowest common denominator - while we are teaching our children French."

Nurseries are supposed to cover six general areas when teaching children. These range from personal, social and emotional development, to language and literacy, knowledge of the world and creative development. All areas have equal importance in inspections.

By the age of five, children are supposed to be able to count to at least 10, recognise different quantities and understand "taking away", talk and use gestures to communicate, retell stories in the right sequence, name and sound the letters of the alphabet and write simple regular words.

Guidance from the Government to teachers emphasises, however, that children must learn by playing rather than through a more formal approach.

Tina Bruce, a visiting professor at London Metropolitan University, said that the more informal methods advocated by Ofsted should be encouraged.

It was "madness" to sit nursery pupils at tables and "stop them from learning".

The emphasis on play mirrors the approach taken in many European countries, such as Denmark and Finland, where children do not start school until they are seven yet perform as well in international tests as English children.

Some nurseries argue, however, that parents here prefer a more structured approach where children's play is supervised and directed by staff.

Lindsey Robertson, 33, whose son Patrick, two, attends Glenfield said that he was happy, secure and learning there.

"You have to give children boundaries to their play," she said. "Even in your own home, you try and make sure they learn as they play otherwise they are running around going from one thing to another."

The mother of two from Stockton said, however, that many parents felt there was too much pressure on very young children to learn.

"Parents and children are worrying about academic standards because of tests and assessments," she said. "At an early age, it can be too much. The most important thing is social interaction and a safe, good environment."

Margaret Morrissey, a spokeswoman for the National Confederation of Parent Teacher Associations, said that nurseries were supposed to prepare children for school and suggested that inspections were not flexible enough.

"Children have to have some guidance otherwise it would be a culture shock when they get to school," she said.

"As long as the basics are right, people who run nurseries should be allowed to get on with it.

"There is a fear that inspections have become clinical and all about ticking boxes. Certainly what they publish for parents now is full of jargon and not much help."

Ofsted employs just under 2,000 staff to inspect and regulate 30,000 nurseries and playgroups and 70,000 childminders in England.

It makes judgements based on the curriculum for three to five-year-olds designed by the Qualifications and Curriculum Authority, called the foundation stage.

A spokeswoman for Ofsted said that the watchdog did not collect specific information on teaching methods but said that good teachers used a range of strategies.

"Children do not make a distinction between play and work, and good quality teachers don't either.

"The best practice includes activities planned by teachers and those children initiate themselves. Teachers can achieve this balance without recourse to formal teaching."