Cutting $144 billion from income tax means reduced funding for essential services that Australians depend on, community groups say.
Malcolm Turnbull's tax plan passed the Senate on Thursday, cutting taxes for people earning up to $90,000 a year, with more cuts up to $200,000 in 2024.
The Australian Council of Social Service said people will miss out because the budget won't be able to fund necessary services.
RELATED READING
Working families 'big winners' in $144b tax cut plan: PM
"The tax cut package is gambling the future of our medical services, aged care services, disability services, and social security payments most of us rely upon at some stage in our lives," chief executive Cassandra Goldie said on Thursday.
"Essential services will lose funding because tax cuts have to be paid for."
Dr Goldie said no one could know what the economic situation would look like in 2024 when the biggest round of tax cuts go through.
"Are we fortune tellers? No, and none us know what will happen to the economy and the budget that far ahead," she said.
"We got into trouble last time a full income tax package was passed in advance.
"The GFC meant our budget was in the red for a very long time and our essential services suffered as a result."
