All school pupils in Northern Ireland could receive a free school meal under plans published by the Department of Education (DE).
But providing a free dinner for all school children could cost over £200m a year.
Providing a free meal to primary school children only or just younger children would cost less.
The department has published a consultation on free meals and uniform grants which includes the figures.
Mayor of London Sadiq Khan recently introduced a free lunch for every pupil at the city's state primary schools.
In Wales, all primary school children automatically get a free school meal but eligible secondary pupils still have to apply.
In September the Scottish government ditched a commitment to expand free school meals to all primary school pupils.
The Department of Education in Northern Ireland previously scrapped a grant to help parents pay for food costs during school holidays.
Education Minister Paul Givan is reviewing the eligibility criteria for free school meals and school uniform grants.
Uniform grants are currently £42.90 for a primary school pupil and a maximum of £93.60 for a post-primary pupil.
His department is already looking at whether a price cap should be introduced for school uniforms in Northern Ireland.
In Northern Ireland, a family is eligible for free school meals and a uniform grant if they receive universal credit and their household income is up to £15,000 per year, after tax.
If families receive other benefits like income support, jobseeker's allowance, or employment and support allowance they should also be eligible.
About 94,000 pupils - over a quarter of the school population - are currently entitled to free school meals.
Givan is exploring if more young people could be entitled to free meals and uniform grants, and how much that would cost his department.
Among the options the department has scoped are to give a free meal to every child up to and including primary three, primary seven or to every child in primary and post-primary school.
According to the department, free school meals could improve a child's "ability to concentrate and learn in school based on them having a nutritionally balanced lunch and establishing positive eating habits".
Providing universal free school meals to all pupils to primary three would cost about £46m a year, while to provide it to all pupils to primary seven would cost £103m a year.
To provide a free meal to all school pupils regardless of income would cost £202m a year.
The department has also looked at raising the household income up to which a family would qualify for free meals or a uniform grant to £20,000.
But its consultation on the plans said that there were "very severe pressures on the education budget".
"An increase in the number of pupils able to access a free school meal would not be affordable from within the current education budget and would require additional funding if any changes are to be implemented," it said.
The number of children living in poverty in Northern Ireland has increased in recent years.
The Assembly's Public Accounts Committee (PAC) recently called the Department for Communities' handling of the Child Poverty Strategy a "catalogue of failures," where children and families are not at its heart.
The consultation on free school meals and uniform grants runs until 14 February 2025.