Bulgarian Prime Minister Boyko Borisov has criticized employers' organizations over their demand that a hike of electricity prices for industrial consumers be postponed.

Power prices for industries are set to rise by 15-20% from August, and the national energy regulator KEVR is to officially confirm the move on Friday, July 31.

On Wednesday, however, employers' associations and trade unions held a protest across the country, calling for the hike to be delayed further until trade in electricity is led by market principles and the Bulgarian Energy Exchange is operational (supposedly next year).

More than 2300 companies took part in the demonstration.

KEVR insists it is not possible to postpone the increase any further, citing the need to tackle the BGN 3.7 B debts piled up by the National Electricity Company (NEK).

Borisov for his part said he would accept any final decision by the energy regulator.

He also accused business unions of having failed to protest over energy projects which helped NEK generate its debt over the last decade.

"Why didn't you stage a strike while Tsankov Kamak [a hydropower plant in Southern Bulgaria] was being built? Why didn't you [rally against] Belene [Nuclear Power Plant], when billions were being sunk there?," the Bulgarian National Radio quotes him as saying.

"These BGN 3.7 B have to come out of our pockets - of the state, of us the people. We keep silent [while] renewable energy [plants] are being built, US contracts [on preferential prices for energy produced by two coal-fired plants] are being made... Why didn't they protest when the contract with the US plants was signed?"

A number of experts have repeatedly warned that the boom of renewable energy producers, for which Borisov's previous government provided a lot of incentives, and long-term contracts setting preferential prices for the energy produced by two US-owned thermal power plants, AES Maritza East 1 and ContourGlobal Maritsa East 3 TPP, are imposing a substantial financial burden on the energy system.

The PM asserted he had done his "best and even beyond that" to secure a fair pricing model.

Before the first protests against the power price hike, held in June, Borisov had sided with employers. Subsequently the increase was put off for a month.