New achievement targets for five- year-olds were set by ministers this week as part of the new "nappy" curriculum.
Ruth Kelly, Education Secretary, said she wanted the proportion of five-year-olds who had reached a "good" level of development to increase from the current 48 per cent to 53 per cent by 2008.
"It may not sound much put like that, but it means an extra 30,000 more children," said Ms Kelly.
Ministers define a "good" level of development for five-year-olds as being able to understand the need for rules, read a range of familiar and common words and try to write for different purposes. The Government originally wanted half of all five-year-olds to reach the target by 2008, but had to revise its view after so many children did well.
Last year, 48 per cent of five-year-olds reached the target but results among authorities varied widely, partly due to how children were assessed as well as their differing abilities.
In Richmond-upon-Thames last year, 89 per cent of children were considered good at writing, compared with 28 per cent in the London borough of Barking and Dagenham.
All schools, childminders and nurseries will be legally obliged to follow the early-years foundation stage from 2008, which is expected to be announced next week.
Parents' groups criticised the curriculum for children from birth to the age of five as "madness" when it was announced last November.
Ms Kelly told an Institute for Public Policy Research seminar this week: "I am acutely aware parents don't want their toddlers sitting exams or undergoing any form of formal assessment.
"Nor do I. This will not happen. Instead, childcare professionals simply observe children - looking, for example, for enthusiasm for learning and good communication skills."