The INTO has told its members in over 100 Irish-speaking schools not to co-operate with Department of Education inspectors until the language is given proper support at primary level.
The union says teachers should not deal with the inspectors until textbooks and materials to support the revised Irish curriculum are made available by the Department.
The general secretary of the INTO, Senator Joe O'Toole, said "as usual the Irish language fails to get the support it requires and as usual teachers are being left to carry the can". The inspectors perform a range of roles in schools, including assessing teacher performance and the general quality of education.
Since September 2000 teachers in Gaeltacht-based schools and in Gaelscoileanna have been struggling to implement the new curriculum without the appropriate teaching materials and textbooks, the union claimed.
"This is an appalling situation and is in fact setting teachers an impossible task, as the successful implementation of any curriculum absolutely depends on the provision of appropriate teaching materials such as textbooks, visual aids and software," said Mr O'Toole.
Section 31 of the Education Act provides for the setting up of a committee to plan and co-ordinate the provision of textbooks and aids for the learning and teaching of Irish.
Mr O'Toole said to date the Minister for Education, Dr Woods, had failed to set up this committee and was therefore in breach of the Act.
"This is yet another example of the government's lack of real commitment to the Irish language and its exploitation of the goodwill of teachers".
The decision to direct members to withdraw co-operation with the inspection system was taken at a recent meeting of the union's central executive.
"Without these resources the Gaeilge curriculum cannot be implemented. The Department of Education must take urgent action on this. The committee should be established immediately so that textbooks and materials can be produced as quickly as possible, but also to ensure that they are of high quality".
He said consultation should also take place with relevant north-south bodies established under the Belfast Agreement to consider getting textbooks and materials used in Northern Ireland.