Traditional phonics should be taught alongside the new play-led foundation phase from the age of three, says the head of a primary school piloting the strategy.
Her comments come as inspection body Estyn conducts a survey on how far the reading technique should be included in the flagship Assembly government strategy.
It also coincides with the launch of a new primary strategy for literacy and numeracy in England.
Sally Francis, head of Mount Airey nursery and infant community school, Haverfordwest, told delegates at a conference on improving the transition to secondary education that it was the duty of every primary school to teach children to read well before they leave. She claimed that the foundation phase alone was not enough to guarantee good across-the-class literacy levels by Year 7.
Mount Airey has been touted as a model for the foundation phase, with a 1:8 teacher-pupil ratio and some head-turning teaching practices. Mrs Francis is a huge fan of the pilot strategy, which is to be rolled out nationally from 2008.
But she told delegates that her duty was to ensure pupils had good literacy skills before they moved on. Educationists have long argued whether phonics (in which sounds are blended to make words) and which type of phonics is the best way to teach children to read.
Mrs Francis said: "Phonics does seem to be in direct conflict with play in the foundation phase. But there is an obligation on teachers that children should be fluent in reading before leaving primary."
Draft guidance produced last year on language, literacy and communication skills in the foundation phase names phonics as one of 13 wide-ranging activities for supporting early reading.
An Assembly government spokesperson said: "It is recommended that a variety of strategies are used in the teaching of phonics and reading, and that professionals use their judgement to choose the methods best suited to the individual needs of children."
Mrs Francis said play-based learning could arm children with language and social skills.
The school has come up with quirky ideas to make learning fun, including using rap songs.
In England, an army of 800 advisers has been drafted in this month to train teachers in a new national primary strategy.
Alan Johnson, Education Secretary, announced reforms focusing on the three Rs in September. Changes include a greater focus on teaching young pupils to read using synthetic phonics.