Play is the best form of education for children of reception age, Ms Erasmus believes: "We're under pressure to get things down on paper, in books. But starting to write things down is too formal for these children.
When they play, they're not aware that they're learning, which is much more comfortable."
The view of Ms Erasmus, early-years and infants co-ordinator at Crumlin high-level primary, in Caerphilly, is supported by the new, play-based early-years curriculum. Though there has been little groundwork preparation early-years and infants teachers are already optimistic about the new plans. Chris Mantle, early-years co-ordinator at Pontysgallog primary, in Merthyr Tydfil, believes they will provide pupils with the time for personal growth often overlooked in their home-life.
"We have a lot of children from socially-deprived backgrounds, and they've been left to play on their own, rather than given structured opportunities," she says. "They need an opportunity to use equipment, such as sand and water, that they don't have at home. And they benefit from added adult input."
But interaction with other children is as valuable as with adults. She cites one child who arrived in her class able only to communicate at very basic levels: "baba pee", for example, when he wanted to be taken to the toilet.
"Adults make an effort to understand what children want to say. But other children won't. They have to adapt and learn in order to be part of the group."
The vital role of play in enhancing communication skills is emphasised equally by Ms Erasmus. While Crumlin primary does not serve a particularly deprived area, she sees poor language ability as the inevitable consequence of a generation reared on video games, by working parents with limited time.
"When my children were that age, they would talk me silly," she says. "Now, parents don't have time to talk to their children. I still have reception children who can't hold a conversation with me. Others have language, but not necessarily the language we want them to have - there are lots of Americanisms."
Extended opportunities for structured play, Ms Erasmus believes, will broaden conversational horizons to adult-sanctioned areas, important in healthy development. Similarly, she welcomes the new curriculum's deliberate focus on personal and social education. This, she says, will enable teachers to fill in the gaps left by parents: "In the world we live in, everyone is in a hurry. Mums think that it's far easier to put a coat or socks or a jumper on for a child than to ask them to do it themselves.
So when reception children have to go down to dinner, a lot just hand you their coats. One boy didn't have a clue - he put his hood over his face.
The new curriculum means we could focus on that."
But, while teachers are enthusiastic about the curriculum itself, many are wary of the practicalities involved. The scope of the foundation stage - all children between the ages of three and seven - means schools will have to reconsider their structure and intake.
"As far as accommodating three-year-olds goes, we just don't have the space," says Bill Bain, head of Builth Wells primary, in Powys. "We are very conscious that we need to develop links with playgroups in town, and I'd be happy to work with them. But that can only be done if you have outreach time for reception staff."
The Welsh Assembly has also said that foundation-stage classrooms should provide one adult for every eight children, and that teachers should have studied child development to degree level. Wales has long had an excess of primary teachers, so few heads are worried about recruitment. But many are concerned that the funding for more classroom assistants and for staff training will not be forthcoming.
"If the assembly can fulfil its promise to train more classroom assistants, it will make a difference, and it will take the pressure off the children," says Mr Bain. "We are pleased these steps are being taken, but we want to be sure that promises will be seen through."
Conference dates: Nansi Ellis of the ATL will talk on Assessment for Learning in Primary Schools on Thursday, May 22 at 3pm; Margaret Wagner of ESIS will talk on Managing The Primary Curriculum on Friday, May 23 at 10.30