Pearse Doherty has hit out at the Dublin government for failing to "provide certainty" for workers and families.
The Sinn Féin finance spokesman criticised the budget proposals for healthcare, housing and the pandemic unemployment payment.
He said: "This budget needed to provide certainty that incomes won't fall off a cliff, that health can weather the storm. This budget has failed to provide that certainty."
Mr Doherty said frontline workers had been let down by the failure of government to tackle the two-tier pay system in the public sector.
He said: "Despite all the fine words, you couldn't find it in yourselves to deliver pay equality for our frontline workers, our nurses, our teachers and other public sector workers. That was the least they deserved."
He also criticised the government as "out of touch" for refusing to reverse cuts to the pandemic unemployment payment (PUP).
He said: "Cabinet colleagues have said that €350 is too much for people who got a shock in their income and lost their jobs, through no fault of their own, mainly because of health restrictions imposed by this government."
He added: "Today the government made these cuts permanent, with thousands set to see their income cut by more than 30% as a result of this budget."
He said much more investment was needed in the health sector, beyond the increase in intensive care beds from 255 to 321 by the end of 2021.
He said: "Limited capacity in our hospitals has undermined our ability to respond to this virus.
"So what are you planning to deliver in 2021? 66 ICU beds we're told, an increase of only 41 on where we are now, because many of these figures that are being announced are double counting. That is nowhere near enough."
He said government had been "indecisive, unprepared and too slow to act".
Mr Doherty said that €6 billion had been left unallocated in the budget, because the government "didn't know what to do with it".
He also criticised the proposal to extend the help-to-buy scheme for aspiring homeowners.
Mr Doherty asked: "What are their big ideas? To extend and expand a discredited help-to-buy scheme. A scheme that will push up the price of homes for first-time buyers.
"Since it was introduced, over 40% of people who availed of the scheme already had the required deposit to secure a mortgage. This is not an affordable housing scheme, it is a sop to developers."
