Under Section 3b of the Income Tax Act, extra pay for work at protected times is tax-free up to set rates of the base wage. For night work the limit is 25 percent, or 40 percent between midnight and 4 a.m. if the work began before midnight. For Sunday work it is 50 percent. For public holidays, and for 31 December from 2 p.m., it is 125 percent. The highest rate, 150 percent, applies to 24 December from 2 p.m., to 25 and 26 December, and to 1 May.