The FSAs are standardized tests taken annually by B.C. children in grades four and seven.
"The FSAs do not help our students learn or our teachers teach in any way," BCTF president Jim Iker told The Early Edition's Rick Cluff.
"In many cases they also cause a lot of unnecessary stress on our students."
Iker repeated concerns the data from the tests is used by right-wing think tank the Fraser Institute in it's annual report card on B.C. schools.
"We should never allow a single test to be allowed to skew school communities against each other and that's what happens every year with those rankings," he said.
The BC Confederation of Parent Advisory Councils supports the tests, saying it provides important information about how effective a school's programs are.
"If a school district instigates a program in early reading, for example, and then another school district instigates a different program in early reading, the FSA can catch some of those differences between the two districts," said BCCPAC president Jim Puddifoot.
Iker said the BCTF is working on a different assessment to measure how students and schools are performing across the province.
To hear the full interview with Jim Iker, click the audio labelled: B.C. teachers oppose FSA tests.