POWER giants are employing too many pen-pushing desk staff, driving up household electricity bills by more than the carbon tax, a new analysis claims.

An Australia Institute report reveals power companies have hired twice as many desk staff as front line techies over the past 15 years and consumers are paying the price.

Electricity prices have surged three times faster than inflation over the past 15 years, it shows.

At the same time, the number of managers has tripled to 19,000 while the sales force has grown six-fold to 6000 workers.

The number of technicians and trade workers grew just 28 per cent to 32,000 - matching the number of clerical and administrative staff.

The report's author, David Richardson, blamed privatisation of government-owned power companies for an increase in the number of backroom workers.

"It seems remarkable that a sales force of 6000 people is necessary to sell a product which everyone needs," he said.

"The managers are growing at five times the rate of the people who actually do the work in producing electricity."

The analysis of Australian Bureau of Statistics workforce data shows the industry has hired an extra 54,000 managers, professionals, clerical staff and sales workers since the privatisation push began 15 years ago.

In contrast, it has hired only 23,000 technicians, trade workers, laborers and machinery operators and drivers.

The management ratio has grown from one manager for every 13 workers in 1997, to one for every nine workers in 2012.

"On the face of it that seems very wasteful," the report says.

Mr Richardson said productivity in the power industry has fallen by one-quarter since 1995, while all other Australian industries have increased productivity by one-third.

"Competition may well be beneficial in theory but it means the firms themselves have had to put resources into selling a product," he said.

"The large increase in clerical and administrative workers may reflect such things as the duplication of billing systems, human resource sections and so on as government enterprises are broken up into smaller `businesses'."

The policy think-tank calculated that the extra backroom staff have added $1.5bn to the industry's costs.

It found power prices from publicly-owned utilities have risen an average of 134 per cent over the past 20 years, compared to 182 per cent for privatised power utilities.

Mr Richardson said proposals to sell power stations in NSW and Queensland were "unlikely" to ease cost-of-living pressures.

"It might even slug consumers with higher bills and worse service," he said. The report shows that power prices have tripled in Sydney - which has both privatised and government-owned utilities - over the past 20 years.

Prices have surged 181 per cent in Melbourne since the Kennett government privatised power utilities 20 years ago.

In Brisbane, where power stations remain publicly owned, prices have grown 167 per cent - the same as in Adelaide, where utilities have been privatised.Prices have roughly doubled in Perth and Darwin, whose utilities are government-owned.

Hobart has publicly-owned utilities but power prices have risen 181 per cent.