new tests for 16-year-olds in basic English and computing skills will not be taken until 2010, pushing back changes to other exams.
Functional skills tests in English and ICT had been planned for 2009 in response to employers' complaints about school-leavers' abilities. But they have been postponed for a year amid confusion about what will be assessed.
Maths functional skills tests will be launched as planned in 2010.
Exam boards have also encountered technical difficulties in working out how the tests will integrate with GCSEs. The Government has said that no one will be able to achieve a GCSE at grade C or better in English, ICT or maths without having passed the associated functional skills test.
The delay has had a major knock-on effect, with reforms to GCSEs in English, English literature, maths and ICT also held back to 2010, a year after GCSE courses in other subjects are due to start.
One senior examiner said a hold-up in reforms to English and English literature would be welcomed by teachers as it would mean longer without change.
The functional skills tests were first proposed in February 2005. The postponement means that they will have been more than five years in development by the time they are first taken.
Simon Wrigley, outgoing chair of the National Association for the Teaching of English, said the delay reflected government difficulty in deciding what the test should assess.
There was also uncertainty about whether "functional skills" reflected only what industry wanted from its new recruits, or whether teachers' views counted.
Ian McNeilly, the association's director of communications, said the new tests were driven by industry.
"Employers think the way to solve their problems is to load another layer of administration and assessment on to already overburdened teachers," he said.
Peter Thomas, a former principal examiner for English literature GCSE, said that while many teachers would welcome a delay, that was not why the decision had been taken.
A Qualifications and Curriculum Authority spokesman said the decision to postpone was made to get the new tests right.
Richard Wainer, of the Confederation of British Industry, said it was important for the new tests to be introduced as soon as possible, but even more vital that the Government got them right.