Social Justice Ireland wants to see the €1bn in next year's Budget spent on housing and broadband.
The group's director, Dr Seán Healy, believes it will be better spent in these areas to help boost Ireland's productivity and competitiveness.
Dr Healy says investing the money in social housing and helping rural Ireland will be more useful than tax cuts.
He said: "Government should spend €1bn fiscal space on infrastructure to improve productivity and competitiveness.
"This would be a far better use of resources than giving tax cuts as incentives to attract ‘Brexit refugees’ from the City of London to Dublin."
Dr Healy said the country needed investment to "address Ireland’s infrastructure deficits" and "to deliver a vibrant, productive, competitive and sustainable economy and a just society".
Michelle Murphy, Research and Policy Analyst at Social Justice Ireland, said: "Investing €400m of the fiscal space to deliver broadband to rural areas will have a much better impact on productivity and competitiveness than tax cuts. It will create jobs, support rural entrepreneurs and local business and rejuvenate rural towns and communities.
"It will also demonstrate Government’s commitment to rural Ireland and to ensuring a more balanced spread of job creation."
Dr Healy said: "The social housing crisis is a further example of the need to prioritise investment in infrastructure and we propose that Government allocate €600m of the fiscal space to social housing in Budget 2017. We also set out proposals for Government to access substantial additional resources for social housing within the fiscal rules.
The think-tank's main proposals are: