Growing student numbers in secondary schools over the coming years will increase pressure on the system to ensure there are enough qualified teachers across all subjects.
An Oireachtas committee heard on Tuesday that school management bodies and teachers' unions have warned of a "crisis" in the supply of teachers.
They say a shortage of substitute teachers at primary level is disrupting children’s education, while at second level there are acute shortages of teachers in subjects such as science, Irish, European languages and home economics.
Deirdre McDonnell, assistant secretary general at the Department of Education, acknowledged that some schools were reporting difficulties in recruiting substitute teachers at primary level and in certain subjects at post primary.
She said a decline in the number of children enrolling at primary level from next year was likely to ease difficulties in sourcing substitute teachers.
However, a growth in student numbers at second level is forecast over the next five or six years.
Eddie Ward, a senior official at the department, added: "The big issue affecting us is probably the population movement of students moving into post-primary. That will cause pressure across all subject areas. We'll have to produce more teachers across all subject areas."
A number of committee members said teacher shortage issues would not be properly tackled until pay inequality among teachers was brought to an end.
Teachers hired since 2011 are on austerity-era pay rates which are lower than their more experienced colleagues.
They also said a culture of casualisation or low hours meant that teaching was not a sustainable career for many new entrants.
Ms McDonnell acknowledged that there was a challenge to attract and retain teachers in the profession given that newly qualified teachers had increased opportunities to travel and work.
However, she said the starting salary for a newly qualified teacher at €35,958 rising to €37,692 in October 2020, was not “unattractive” in the context of graduate salaries generally.
She said new entrant pay was an issue that related to pay policy across the entire public sector and was at the centre of talks between trade unions and the Department of Public Expenditure.
On the issue of casualisation, she said the department had introduced measures to combat this, including accelerated access to permanency through contracts of indefinite duration and requiring schools to give preference to teachers on less than full hours as additional hours become available.
She said a steering group on teacher supply would consider whether additional measures in this area might be taken.
At primary level, she said a number of measures had been put in place to increase the supply of teachers including an expansion in post-primary teacher education courses.
She said initial figures indicated there was a rise in applications for teaching courses this year.
Committee chairwoman Fiona O’Loughlin TD said she felt the department’s presentation on the issue was “over-optimistic” and said the teacher shortage problem was more acute.
She said surveys indicated that 90 per cent of primary school principals were reporting difficulties hiring substitutes, while many secondary school management bodies said there were acute problems finding qualified teachers in key subjects.
Her colleague Fianna Fáil TD Thomas Byrne TD said the teacher supply issue was a crisis that was "not being dealt with with any sense of urgency or purpose by the Minister for Education".
He said ending pay inequality should be a key priority, while there should be a more aggressive campaign to encourage teachers based abroad to return home.