The Irish Congress of Trade Unions says an €800m adjustment is all that is needed in the next budget.
In its pre-budget submission today, ICTU says the Government should invest in a social and affordable housing programme.
It also wants households earning up to €80,000 a year to avail of free water charges, to help ease the burden on lower and middle incomes homes.
General Secretary, David Begg, says an €800m budget adjustment would suffice, rather than the €2bn figure that has been suggested.
Mr Begg said: "Our €800m calculation is based on our view that the structural deficit, as it is called, that's the difference between what you raise in tax and what you spend every day, is going to close and is almost closed.
"Most of the money that we have to spend has to do with our debt."