Goanna Energy consultant Marc White said the public did not have the true picture of the state-owned energy generator.

Despite posting a record $238 million profit last week, Mr White said the business was likely to soon be faced with huge repair bills for its ageing infrastructure and had already flagged a drop-off in profits due to plans to axe the carbon tax.

All three political parties have ruled out selling Hydro, but Mr White urged them to reconsider.

"I expect that the state's finances are in such a state that there is no choice but to start looking at the sacred cows," Mr White said.

His call follows the collapse of the sale process for the state-owned electricity retailer Aurora Energy late last month.

Mr White has surveyed six interstate electricity companies and found Hydro's wholesale market dominance was a major deterrent to potential new entrants to the state's residential electricity retail market.

At the time Aurora was pulled from sale, Energy Minister Bryan Green dismissed suggestions the government's failure to tackle Hydro's monopoly was behind the collapse and blamed other reasons for being unable to achieve a sale.

Mr White said Aurora now faced a difficult future in a competitive market from next July.

"It's saddled with a high cost to serve if new retailers come to cherry pick their customers. What I do know from experience is you get to keep your unprofitable customers because no one will take them off you," Mr White said.