Many households in the eastern states face a sharp jump in their power bills from July 1 as retailers raise prices on some contracts well above the increases allowed to benchmark rates, just as consumption soars due to winter weather.

One NSW customer of government-owned Red Energy this week was informed their daily service tariff would surge 41 per cent and their usage tariff by 14.4 per cent from the start of the new financial year, according to a letter seen by AFR Weekend.