The general secretary of the ASTI has said it is time to end the two-tier pay structure for new teachers.
Associations representing both gardaí and nurses have also called for the Government to tackle the issue across the public service for new recruits.
The issue was raised after an agreement was reached for full-time local authority firefighters which addressed the differences in pay for firefighters recruited since 2012.
ASTI general secretary Kieran Christie said that people doing the same work should be paid the same wage.
"It has to go, it has to be addressed because it's creating an enormous morale problem right across the teaching profession," he said.
"It's as much a damage to the morale of those who are on the higher salaries as those who are on the lower ones because collegiality is one of the key cornerstones of any staff room among teachers.
"It's just got to go."