The secondary teachers' union, ASTI, has entered the dispute between the Minister for Education and primary teachers by warning against "starving" second-level schools in order to increase funding to under-resourced primary schools.
Its president, Mr Michael Corley, said it was "naive and unhelpful to suggest that second-level schools be targeted in the manner suggested by primary teachers' leaders.
"The Government needs to provide extra funding for the entire education system, and with a revenue surplus of £2.5 billion forecast between this year and next, there is no reason why this should not be a priority for immediate action."
However, INTO's general secretary, Senator Joe O'Toole, stressed that primary teachers were not saying second-level schools were overfunded or that their funding should be reduced.
"We're not trying to eat anybody else's dinner. We're trying to make the Minister live up to his commitment to bring us up, not to bring them down," he said.
"We fully support their need for extra funding. All we're saying is that primary schools have lagged seriously behind all other levels."
Mr Corley said the State should have dealt with the problems in primary schools 30 years ago.
"We feel that basic education for students runs until 16 years of age. The reality today is that students' employment prospects are determined by the need for basic numeracy and literacy skills, but even more so by the need to have completed second-level education.
"Second-level schools are equally starved of funds. That is why parents at second level are forced to raise funds `voluntarily' to meet the 20 per cent gap between State funds provided and everyday running costs."
He said Department of Education figures showed that in 19931994 the non-teachers pay element of expenditure on second-level education was £308 per student. In Northern Ireland it was £713.
Similarly a typical 670 student second-level school in the North had 49 teachers, compared to 36 in the Republic. Expenditure per second-level student in the Republic was only 54 per cent of the OECD average.
Mr Corley said the £127 gap between the per-pupil capitation amount paid to primary and second-level schools, which the INTO wants the Government to close, was the same in every other education system in Europe.
"Second-level schools are bigger, house more students, require facilities and equipment such as science and language laboratories, computer labs, guidance/counselling facilities, vocational/technical facilities, PE facilities, and art and music rooms, which are far more costly than would be required at primary level.
"Classes at second level are subject-based, requiring more facilities, rooms and teachers, and are not simply rooms to house classes of the same number of students all day long. For this reason, the capitation rate paid is higher."
Mr Corley said: "The last thing we need is calls for funding to be frozen at second level in order that primary schools alone be assisted. We do not need lopsided debates which deflect from the need for extra funding for all sections of the education system."