The national curriculum in England is to be revised so children are taught to read primarily using the method known as synthetic phonics.
Fostering an early love of reading is regarded as crucial
The approach is a key recommendation of a review headed by former Ofsted inspections director Jim Rose.
He says phonics - letter sounds - must happen alongside paying attention to speaking and listening.
The government and the Tories back the findings. The Lib Dems say it should be for teachers to decide what is best.
And Steve Sinnott of the National Union of Teachers said teachers would be bemused because phonics was already a national curriculum requirement for infants.
The current approved strategy involves a mixture of approaches.
Phonics focuses on sounds - rather than, for example, having children try to recognise whole words.
In the widely-used analytic phonics, words are deconstructed into their beginning and end parts, such as "str-" and "-eet".
In pure synthetic phonics, children start by learning the sounds of letters and of letter combinations: "ss-t-rrr-ee-t".
Only once they have learnt all these do they progress to reading books.
The final Rose report, published on Monday morning, recommends that for most children, systematic phonics teaching should start by the age of five.
There should be extra help for children who fall behind.
Head teachers should make phonics the priority - and set ambitious targets for what children should achieve by the time they finish primary school six years later.
In the most famous experiment, in Clackmannanshire, children taught using synthetic phonics were years ahead of their contemporaries by the time they moved on to secondary school.
The method is already endorsed by the Scottish Executive.
Critics say it might teach children to read - but not necessarily to understand what they are reading.
And research commissioned by England's education department said the evidence base for using synthetic phonics was weak.
The Westminster government is proud that its national literacy strategy, introduced in 1998, has seen the proportion of 11-year-olds reading at the expected level for their age rise from 67% to 84%.
But it acknowledges that one in five children still does not reach the necessary standard in English overall and, as a result, their teenage learning is hampered. Ms Kelly said she accepted all the recommendations in the report and had launched a programme of training for teachers.
She said: "I am clear that synthetic phonics should be the first strategy in teaching all children to read."
Her department will work with the Qualifications and Curriculum Authority on how best to embed this in the national curriculum.
Mr Rose said the best schools already use systematic phonics teaching within "a language-rich curriculum".
He said he had reached his conclusions because synthetic phonics combines both word recognition - cracking the alphabetic code - and comprehension.
"This is a programme for beginner readers," he said. "This is for children starting out on the way to reading and undoubtedly the evidence shows that this is the most successful route."
However, he stressed that phonic work was only "part of the story".
"It's not the whole story but it's an extremely important step because unless you can actually decode the words on the page you will not be able, obviously, to comprehend them."
The Conservatives campaigned for such an approach during last year's general election.
Shadow schools minister Nick Gibb said synthetic phonics should be happening in every primary school.
"The alternative 'look and say' approach has, over two generations, led to poor literacy levels in this country and the associated problems at secondary schools of low levels of attainment and disruptive behaviour," he said.
Liberal Democrat education spokeswoman Sarah Teather said being overly prescriptive approach would not leave any flexibility for teachers to decide what was best for the children in their class.
"Schools should get guidance based on the latest research but the precise mix of methods used in classrooms is a matter for teachers working with individual pupils," she said.
"Phonics is only one tool to help children learn the English language. The national curriculum neglects communication skills and more needs to be done to address speaking and listening in the early years."