The executive committee of the Teachers’ Union of Ireland (TUI) is to unanimously recommend rejection of the proposed public service agreement on pay.
The proposals, issued by the Workplace Relations Commission (WRC), would deliver an extension to the Lansdowne Road Agreement.
The benefits to different income groups would range from 7.4% to 6.2% over three years.
The agreement runs from 2018 to 2020.
Proposals include restoration of pay cuts and ensure that over 70% of public servants will be making a further permanent contribution to their pensions.
The Department of Public Expenditure says the agreement allows for "on-going co-operation with change and productivity improvements and industrial peace until 2020".
Public Expenditure Minister Paschal Donohoe said earlier: "These proposals aim to award pay increases for public service staff across the coming years in line with what is affordable to the State, put pension provision on a more sustainable footing and secure industrial peace so that our public service remains a rewarding place for those who work in it and continues to deliver for those who depend on it".
But speaking after a meeting on Thursday evening, TUI president Joanne Irwin said that it would be "unconscionable" for the union to recommend acceptance of an agreement that effectively "copper-fastened a system of pay inequality".
The union described the draft document's failure to properly address a "discriminatory, inequitable two-tier pay system" as "completely unacceptable" and said that the process of pay equalisation requires acceleration rather than further delay.
TUI’s over 17,000 members will be balloted on the draft agreement in September.
Ms Irwin said: "We acknowledge the pay restoration elements in the proposed document.
"However, an unwinding of the unacceptable, unfair and inequitable two-tier pay system was the key priority for TUI on entering the recent negotiations.
"Wherever and whenever possible, we vigorously pushed the issue forward".
"It remains completely unacceptable to us that two colleagues, recruited within days of one another, are paid significantly different rates for carrying out the same work.
"TUI has prioritised and campaigned on this issue and some progress has been made."
"The draft proposed agreement would have the effect of blocking further progress for at least three years", she added.
