Published Thursday, 28 May 2009
Meeting in Belfast on Thursday, the five main unions also called on politicians to agree a method of transfer to replace the 11-plus.
David Canning, principal of Strabane Primary School, said principals were very concerned for the health and wellbeing of primary 6 pupils.
"Many of these pupils will find the experience highly stressful and we fear that they will not perform to their true ability."
Audrey Stewart, a former principal of a primary school in Larne, also said principals and unions had serious concerns about the validity and reliability of the tests.
Details of tests in English, Maths and Science have already been sent to parents.
The final 11-plus examination was held in schools here in November 2008.
How exactly pupils will transfer to secondary-level education in the future remains unclear.