The first of a series of 15- to 30-minute tasks, on data handling, will be made available to schools in October. Another, on modelling, will follow in March. Two further tasks will be released during 2008.
The tests, which will be marked by computer, are designed to be used by teachers to work out pupils' strengths and weaknesses and to plan their learning needs.
They represent the outcome of a five-year pound;26 million project that was to lead to a statutory key stage 3 national test in ICT from 2008. In January, the Government abandoned this proposal and instead said that tests would be made available to teachers at any time they thought their pupils were ready to take them.
At the Institute of Educational Assessors' annual conference in London, Sue Walton, of the National Assessment Agency, said the new assessments would be "short, stand-alone tasks that can be fitted into lessons".
Schools will be able to set them for pupils throughout the key stage and they will provide information on which level the child has reached. The tests will be set at a two-level difficulty range, covering levels three to four, four to five and five to six.
They will be delivered via the current computerised key stage 3 national test infrastructure, though without the current requirement that pupils are given passwords. The computer will generate reports on pupils' strengths and weaknesses as soon as they finish the test and produce information on the performance of a whole class.
The National Assessment Agency is promising a range of support materials for the tasks, including a progression grid, showing how pupils are faring in each area of the curriculum measured by the tasks.