Padraig Walshe was speaking in Carrick-on-Shannon, Co Leitrim, where around 5,000 farmers demonstrated against cuts in farm spending announced in the budget.
The IFA estimates that the Budget measures will cost farmers in the west and north-west nearly €40m.
Since the Budget in mid-October, farmers have been holding meetings all over the country to voice their anger over cuts in investment programmes and in retirement and some livestock schemes.
The IFA is accusing the Government of taking the easy option by cutting the income of farmers on marginal land mainly in the west of Ireland.
Mr Walshe said cuts in the suckler welfare and the disadvantaged areas schemes are a direct attack on the viability of low-income farmers.
