Social Justice Ireland has called for the special VAT rate for the hospitality sector to be scrapped.
The group's pre-Budget submission said that raising the 9% rate to 13.5% would provide an extra €190m for the Government to spend.
The group is also calling for an extra €500m to be spent on social housing, and for €300m more to be spent on rolling out rural broadband.
It is also asking for a minimum effective corporate tax rate of 6%, and for the Government to introduce a levy on undeveloped sites and empty homes.
Sean Healy, Director of Social Justice Ireland, says the Government has to grapple with the big issues affecting the country.
"Budget 2018 should be designed so that it is both economically sound and socially fair," he said.
"These twin objectives are both realistic and achievable. However, they need to be underpinned by a clear policy commitment to achieving both.
"Most Irish people want to see an end to homelessness, social housing shortages, hospital waiting lists and child poverty.
"They want to see the lack of affordable childcare addressed, investment in rural broadband, and much more. These should be the priority targets of Budget 2018.
"Ireland is not going to solve its major challenges in a single budget or in a single term of office of any Government.
"Addressing the country’s current challenges effectively will take a decade or more. Decisions will have to be made regarding priorities and sequencing.
"All sectors of Irish society should be involved in shaping and delivering these decisions."