A number of measures announced in the Budget last month came into effect today, including cuts to child benefit and the respite care grants.
Monthly child benefit payments have been reduced by €10 to €130 for the first and second child, and by €18 for the third.
There is a 19% reduction in respite carer grants, to €1,375.
The ending of employees' PRSI allowance will mean all PAYE workers will pay PRSI at 4% on all their earnings.
Medical card holders will see each prescription charge trebling from 50 cent to €1.50.
The New Year also brings in cuts to back-to-education allowances and reduced payment periods for jobseeker benefit claimants.
Motor tax costs also rose today, dependent on a vehicle's age, engine size or emissions.
There are also increases of up to 2% in vehicle registration tax.
There is further bad New Year's Day news in the form of motor and health insurance price hikes.