The Department for Education and Employment has delayed the tests by a week, to allow schools to prepare for them after the late Easter break. But many schools have already arranged residential visits, and in some cases up to pound;1,000 is being demanded if they cancel.
Nick Tate, chief executive of the Qualifications and Curriculum Authority, has responded to the complaints by suggesting children sit the tests during their field trip, as long as the papers remain secure and a responsible adult is present to administer them.
David Hart, general secretary of the National Association of Head Teachers, has written to Dr Tate, saying schools in this position must be able to sit the tests at another time.
He said Dr Tate's suggestion was unacceptable. Although the association welcomes the date change in principle, Mr Hart says the QCA gave insufficient notice.
He said: "We talked to the QCA about changing the date as long ago as autumn 1998. The delay has put some schools in a difficult position. The only option is for them to have permission to administer the tests on a different date.
Mark Biltcliffe, the NAHT Warwickshire president, has written to Dr Tate about schools in his area which have booked trips. He said: "The danger is that schools will refuse to cancel the visit and will not do the tests according to the regulation, but will do them another week without permission, mark them themselves and give parents the results. This would mean they would not feature in the league tables."
A spokeswoman from the QCA said schools should try to rearrange their trips, but where this is not possible they will have to show proof before being considered for a test timetable change.
The DFEE will decide on compensation next month - schools that have suffered financially must write to its assessment team.