Social Justice Ireland says the Government should not repeat the same 'fundamental mistakes' made in previous budgets for the country.
It is calling on them to ensure the budget focuses on well-being and social progress.
In its Budget Choices 2021 plan, it says the State must spend a lot to support incomes for a lengthy time.
It says when we emerge from public health restrictions into recovery, sustained public investment is crucial.
It also says the State should begin to plan now for the additional tax measures, over the long-term, to finance the Government expenditure required for services and income supports.
Social Justice Ireland CEO Dr Seán Healy told Breakfast Briefing we need to get people back into the workforce.
"We need to obviously focus on things like restoring the demand for labour, because work is so important, and we have to try to ensure that we're reducing unemployment - and the budget should be working in that direction.
"That means we have to strengthen the economy, and everybody wants a thriving economy."
"For the past 20 years plus, we have basically made a fundamental mistake we should not repeat: and that is that we say 'get the economy right and everything else will follow' - that's simply not true".
"The reality is that it's not just the economy, stupid - to redo Bill Clinton's slogan from way back when.
"We're saying that if you want to have a thriving economy, you must also have good infrastructure in areas like housing, public transport, rural broadband and things like that.
"And you must also have good social services in areas like health, and education and childcare and elder care.
"If you don't do the infrastructure and the social services at the same time as you're trying to drive a thriving economy, you won't made your goals - if you like - on the economy side.
"And it's very important that the budget should tackle the rising inequality that Ireland has been experiencing for the last decade or more.
"And we should also face up to the fact that we haven't done well in reducing poverty: we need to bring the numbers down.
"At the moment, there's 680,000 people in poverty - and that means in effect... there's over 100,000 people with jobs who actually are living in poverty.
"To tackle that issue of the working poor we suggest he should make the main tax credits refundable, so that people benefit from the full value of the tax credit.
"At the same time there should also be a move towards getting social welfare rates back to where they were - which was 27.5% of gross average industrial earnings".
Dr Healy said to fund these proposals, there needs to be tax reforms - including in corporation tax.
"We're basically looking for a fairer tax system, a minimum effective rate of corporation tax - 6% - and we would also be proposing the standard rating of tax breaks on things like private pensions and all these tax breaks that go on - they should only be given at the standard rate, we would argue."
"But the bottom line in it is obviously at the end of the day, the Government is going to have to borrow an awful lot more than it actually takes in - and what we are saying about that is the fiscal stance should basically recognise that that's the reality."
He suggested this should be done on low interest rates in a special programme developed in Brussels "in the same way we paid back debts after the Second World War or the First World War".