Professor David Hopkins, head of the Government's standards unit, has written to all education authorities outlining what is expected from them in helping improve standards.
He said that support should focus on individual pupils, using booster classes and ensuring teachers and pupils are prepared for the changes to the English and maths tests this year. He added that literacy and numeracy consultants will be given more details on how to improve results.
Their role will include ensuring that all schools have ordered the new Year 5 optional test papers for English and mathematics.
The Association of Teachers and Lecturers, whose members include literacy and numeracy consultants, has protested about the letter.
Sheila Dainton, ATL education policy adviser, said: "We are taking immediate steps to remind members that the optional tests are precisely that, optional.
"We do not believe the Standards and Effectiveness Unit has the authority in law to instruct schools to administer tests and if they had that authority we would expect the tests to be made available free of charge."
Graham Lane, education chair for the Local Government Association, said:
"The Department for Education and Skills does not seem to understand that headteachers run schools. It seems to think it can issue edicts."
The Qualifications and Curriculum Authority has developed new optional tests for Years 3, 4 and 5 to reflect changes to the compulsory national KS2 tests that were made this year.
But the QCA's website points out that in order to ensure delivery of the tests before Easter, schools should have placed their order by December 13.
A Department for Education and Skills spokesman said: "The Year 5 tests are made available to support schools, and the vast majority of primary schools have ordered them."