The Teachers Union of Ireland Executive is being criticised for failing to reject the Government's proposals on 'new entrant' pay.
TUI Grassroots says the plans will ensure those who enter the public service in future will be treated much less favourably than those who came in before 2011.
In a statement, the activist group says the Teachers Union of Ireland has admitted these proposals do not deliver equal pay.
The group said they will have a meeting on Monday about the issue.
Their Facebook post read: "The TUI Executive has decided to put the proposals on new entrants to ballot without a recommendation. The ridiculous statement on the website says very clearly 'that the measures do not deliver pay equality and will not tackle the recruitment and retention crisis currently afflicting second level schools'.
"Did you get that? 'do not deliver pay equality'. So we have not achieved equal pay. So why is the Executive not opposing these proposals which will institutionalise unequal pay?
"There was an awful lot of rhetoric from the EC and our past president at Congress about delivering equal pay now. They have failed. Failed utterly.
"Our current president says: 'Irrespective of the choice members make in the ballot, pay equality will remain the union’s main priority until it is secured..
"What utter rubbish. If these proposals are accepted that will be the end of the pay equality campaign. And new teachers and lecturers will be left with suppressed entry pay."