Almost 6,500 ESB customers who run businesses from their home are facing price increases of up to 4.4 per cent under proposals submitted by the company to the energy regulator.

The proposals have yet to get the agreement of Tom Reeves, the regulator, but the ESB is claiming that prices need to be re-balanced and these customers should pay a more "cost reflective tariff".

The ESB claims that residential business premises customers are not paying for the full cost of their electricity.

For example, the company claims that for historical reasons the prices paid by the customers does not include a charge for the transportation and distribution of electricity. They also point out that many of these customers pay mainly at domestic rates, rather than business rates and this needs to be re-balanced.

The changes proposed would effect those paying their bills in the normal way but also those paying on the special night saver rate. This rate involves customers running household items at non peak hours, thereby making savings.

The latest application from ESB comes after a recent announcement of a 19.7 per cent increase across the board in electricity prices.

This announcement drew sharp criticism from consumer groups, opposition TDs and small business groups.

The latest ESB document states: "These changes are proposed as a strategy to have a more equitable and cost reflective residential business premises tariff, and to move customers that do not require to be on a such a tariff to a more appropriate cost reflective tariff." The changes would kick in from January 1st.

This week trade unions joined together to call for the energy regulator to rescind the 19.7 per cent increase in electricity prices amid falling fuel costs.

David Begg, the general secretary of the Irish Congress of Trade Unions, said the Commission for Energy Regulation (CER) was not taking into account the possibility of a drop in fuel prices.

Mr Begg wrote to the commission asking that the rise be replaced with a fuel variation charge on bills. Under the charge, the amounts added to the standard domestic electricity bill would vary depending on the oil prices at the time.