Sinn Féin leader Mary Lou McDonald has said Budget 2027 must ensure that working people and families come first and accused the Government of "leaving big money behind".
The party has consistently stated that prices are spiralling out of control and the Government has left people worse off.
Sinn Féin said that its proposals would put money back in the pockets of workers and families.
To do that, it wants to abolish the Universal Socail Charge (USC) on the first €40,000 people earn.
It is also seeking the removal of carbon tax on home heating oil along with the return of energy credits this winter.
Speaking on RTÉ's Morning Ireland, Ms McDonald said Sinn Féin has identified several areas where the Government could raise more tax revenue.
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"For instance, vulture funds, large investment funds that invest in what are called build to rent. People will be familiar with these developments all across the country.
"They're very large, very expensive rental units held by these corporate landlords. We think it's absolutely scandalous that the rent accruing from those extortionate rents does not attract corporate tax.
"That is the Government currently leaving behind more than €300m in tax that ought to be paid to the Irish State and we believe that should stop," Ms McDonald said.
She added: "Similarly with sweetheart deals with the banks who do not, like any other business, pay the normal level of corporate tax. That's leaving behind a further €300m and so on and so forth."
The Sinn Féin leader added that the party's finance spokesperson, Pearse Doherty, will be moving legislation, possibly tomorrow, "specifically in respect of home heating oil".
She also said "there's been a huge jump in costs… more than €100 in the course of just one week" for heating oil.
Language test for Irish citizenship 'reasonable'
Ms McDonald said a language test for people seeking to obtain Irish citizenship is "reasonable", adding Sinn Féin would focus on implementing a system that is fair, effective, and resourced.
The Dublin Central TD described gaining Irish citizenship as a "great honour".
"We have no objection to having a structured pathway towards achieving that. I think that's reasonable."
"We are certainly open to reviewing pathways to it, making sure that they are fair and reasonable," she said.
Ms McDonald added: "I think myself, things like integration into the community, things like a working knowledge of Gaeilge or English or ISL, I think all of those things are reasonable things."
"Systems that are responsive to community needs and of course the system that is always and vigorously and avowedly anti-racist. Those are the pillars of what we've talked about."
The Sinn Féin leader accused Government policy of being "utterly irresponsible and unreasonable" for a long time.
"Unreasonable in the way that they manage these matters, and they placed international protection applicants, vulnerable people themselves in many, many cases into communities that were literally bereft and struggling.
"I'm not talking about communities that just have a minor shortfall in resources. I'm talking about communities where there was literally nothing, no facilities for communities.
"But it's not my job to scan the country to find sites like that," she said.
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In relation to Sinn Féin's policy document that set out criteria for where asylum seekers could be located based on housing, health, schools, Ms McDonald said, "our role is to set out the policy parameters and the means by which the State and the public authorities should approach these issues".
Ms McDonald was asked whether Sinn Féin agreed with the Government's stated position to reduce immigration.
"There's a particular issue around housing in Ireland and getting accommodation," Ms McDonald said.
"So any responsible government has to have in their line of sight all of those matters when they calculate how many permits in any particular sector might be allowed, how you manage student visas, and the whole range of other elements of that policy," she added.
Ms McDonald said whether it is people coming to Ireland on student visas or work permits or whether those seeking international protection, there needs to be a system that is "based on clear, transparent rules that are resourced and that are enforced."
She said the system needed to be cognisant of the community and the societal needs of Ireland, but also the labour needs of the economy.
Ms McDonald said she believed it was only recently that the Government was "moving close" to the Sinn Féin position of listening to communities and protecting communities regarding international protection.
She said: "at the core of this is a matter of proper management, of proper resourcing, and having a system that is responsive and efficient, and a system and an approach that listens to communities," adding that Sinn Féin had pressed this case "very, very strongly."
Ms McDonald said a budget has not been set in Northern Ireland because "London holds the purse strings" and "chronically and consistently" underfunds the North.
There is a cost to partition, she said, and one of those costs is that we are unable to deliver in Northern Ireland in the way that is the most efficient and effective.
The Sinn Féin leader said the 'Good Jobs’ bill is being actively blocked by the DUP.
McDonald says preparations for united Ireland need to commence
Ms McDonald has accused the Government of "living in a fool's paradise" in its approach to Irish unity, and of acting irresponsibly.
"It is now absolutely imperative that we have orderly, responsible dialogue and preparation for referendums, in advance of the referendums to ensure that we can have a process that is democratic, peaceful, and orderly," she said.
"The issue is, long before a date is set, the democratic preparation has to be under way, and we press that case consistently.
"And I am astonished at the the fact that some in Government still would persist with the notion that we shouldn't talk about this issue, that we shouldn't prepare.
"That to me is extremely irresponsible."
She said preparations for a referendum on a united Ireland need to commence now.
Ms McDonald also said she believes President Catherine Connolly will "discharge her duties admirably" when she meets US President Donald Trump on Saturday.
The Sinn Féin's parliamentary team is meeting in Dublin today to finalise its priorities for the new Dáil term.
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A week out from the resumption of the Dáil, Sinn Féin has pledged to work with other opposition parties to show there is an alternative to what it brands the "stale politics" of Fianna Fáil and Fine Gael.
There will be discussions too on Irish unity as well as a focus on maintaining the Triple Lock.
Next week, Michelle O’Neill and Mary Lou McDonald will travel to Cardiff to meet Scotland’s First Minister and SNP leader John Swinney and Plaid Cymru leader Rhun ap Iorwerth.
The party said that all those involved in these upcoming discussions believe that nations have the right to choose their own future.
Trump visit an 'opportunity' to address issue of Palestine
Ms McDonald said she hopes President Catherine Connolly will raise the case of Palestine with President Trump during their meeting this weekend.
The Sinn Féin leader was asked about the visit of the US President ahead of the party's pre-Dáil think in in Malahide this morning.
Ms McDonald said: "I would imagine, and I would hope that, given the opportunity, that she would raise the matter, particularly in regards of Palestine and the United States' ongoing facilitation and arming of Israel, I think, given the opportunity, I would hope that the president would raise that."
She said that she recognised the meeting would be brief, but said that President Connolly's views on these matters were "very well documented."
"By contrast, the Taoiseach will have every opportunity again to very clearly set out the views and position of the Irish state and the Irish people, and I believe that he must do so very, very clearly and very firmly," she added.
Additional reporting: Juliette Gash
