The national minimum wage is to go up by 38 cents to €6.35 per hour from October 1st.
The increase is the second since the introduction of a minimum wage in April 2000 at a rate of €5.58 per hour.
"The national minimum wage continues to have a significant impact on the earnings of many thousands of low-paid workers," the Tánaiste, Ms Harney, said in a statement.
She warned Government inspectors would visit employers to ensure the new rate was being paid.
Ms Harney reminded workers and employers that sub-minimum rates are paid to certain categories under the terms of the National Minimum Wage Act which took effect from April 2000.
Among those workers not eligible for the minimum rate are under-18s, first time job entrants, those in training or study. The Tanaiste pointed out however that their rates would also increase.