President Michael D Higgins has attacked some overseas countries for putting their own selfish interests before the plight of the world's starving.
Large companies behind land-grabs in poorer countries were also fuelling evictions, poverty and conflict just to pump up their own profits, he told a talk on global hunger.
"In what one could view as a predatory fashion, countries and corporations are taking over agricultural land in developing countries to secure their own food security or boost corporate speculative profits at the expense of the developing world," he said.
Mr Higgins was speaking at the opening of a two-day summit entitled Feeding the World in 2050, which is part of Ireland's six-month European Union Presidency programme.
Telling the conference that chronic hunger affects one in seven people around the world every day, Mr Higgins said dire poverty was being made worse by gross inequalities "that scandalously persist".
"Eradicating this poverty and its consequences is, I suggest, the greatest moral and ethical challenge we, as a global community, face today," he added.
While poorer countries are desperately seeking investment to help them produce food, there is clear evidence that some powerful states were serving their national interest rather than their international responsibility to the hungry, said the president.
Without naming and shaming the alleged offenders, he berated food multi-nationals who have gained the power to undermine national regulatory agencies in developing countries.
"Such corporations seek to open up markets for profits and the subsequent changes have tended to favour large-scale producers and global agribusinesses, frequently at the expense of local producers who grow food for local markets, thus compounding problems of inequitable land ownership," he said.
Farmers in the developed world are being subsidised with public money to produce food which may be sent as cheap or free aid to poorer countries, he pointed out.