Ireland cannot use the €13 billion in disputed tax it collected from Apple to help people affected by Covid-19, the Taoiseach has said.
Sinn Fein leader Mary Lou McDonald said the state could "right this minute" use the account where the funds are being held to help the Irish economy.
In 2016, it was ruled by the European Commission that the Irish state had given undue tax benefits worth €13 billion to Apple, which is illegal under EU state aid rules, and said it allowed Apple to pay substantially less tax than other businesses.
Ireland was ordered to recover the illegal aid, plus interest, however the state and Apple are currently appealing against the ruling.
Political rivals have claimed this shows Fine Gael's dedication to corporations rather than the public.
On Monday, Taoiseach Leo Varadkar dismissed Ms McDonald's suggestion.
"Mary Lou McDonald should know better, the Apple money is in an escrow account and that is where it is being held until the European Commission decides where that money is going to go.
"The European courts will decide whether that money either belongs to Apple or comes to the Irish revenue commissioners and then has to be distributed out among the countries of Europe.
"It's not ours to take and it's now before the courts.
"She should know better before coming out with that kind of rubbish."
Mr Varadkar said a significant financial package will be announced this week for those who have lost their jobs due to Covid-19 and others at risk of becoming unemployed.
Responding to Mr Varadkar, Ms McDonald said: "I would say to the Taoiseach, we need an income support scheme. I am not interested in having a squabble with him as to where the monies are raised. It is going to be an expensive scheme and it is going to be necessary.
"It is going to be the wisest money we will invest in our workforce and in our economy at this time of emergency.
"I want the Government to go further than they have gone so far. I think at this stage, delay is dangerous.
"It is unacceptable to leave tens of thousands of workers in conditions that are not safe, where they know they risk transmitting and contracting this virus and bringing it home to their families and children.
"This emergency requires us to be innovative. Rather than the Taoiseach telling us where the money won't come from, he needs to now apply himself to secure the necessary funding because this income support scheme has to happen."