Elected officials in Texas say the state should help pay some of the eye-watering electricity bills sent to residents after a devastating and deadly winter storm that caused widespread blackouts.

Texas has a highly unusual deregulated energy market that allows consumers to choose between scores of competing electricity providers.

Some providers sell electricity at wholesale prices that rise in sync with demand. Those prices skyrocketed as a record-breaking freeze gripped a state unaccustomed to extreme cold, killing at least two dozen people and knocking out power to more than 4 million people at its peak. Some 30,000 people were still without power on Sunday, Texas Governor Greg Abbott said.

As a result, some Texans who were still able to turn on lights or keep their fridge running found themselves with bills of $US5,000 for just a five-day period, according to photos of invoices posted on social media by angry consumers.

The Dallas Morning News said one provider offering a wholesale tariff plan had urged its thousands of customers to switch suppliers ahead of the storm to avoid high prices, but many found it would take too long to change their provider.

"The bill should go to the state of Texas," Houston Mayor Sylvester Turner said in an interview with CBS News on Sunday.

"When they're getting these exorbitant electricity bills and they're having to pay for their homes, repair their homes, they should not have to bear the responsibility."

Fort Worth Mayor Betsy Price told CBS both the state and the federal government should be expected to help with the bills.

US senator Ted Cruz, who was forced to cut short a family holiday to Mexico after public outrage, also distanced himself from the free-market system he had previously praised.

"This is WRONG," Mr Cruz wrote on Twitter. "No power company should get a windfall because of a natural disaster, and Texans shouldn't get hammered by ridiculous rate increases for last week's energy debacle. State and local regulators should act swiftly to prevent this injustice."

Mr Abbott called an emergency meeting to discuss the problem, saying in a statement that the state had a responsibility to ensure Texans "do not get stuck with skyrocketing energy bills".

On Sunday, the governor told reporters that the Texas Public Utilities Commission would order electricity companies to pause sending customers electricity bills.

The commission was also issuing a temporary moratorium on disconnection for non-payment, Mr Abbott said.

Separately, Texas Attorney-General Ken Paxton issued civil investigative demands to power companies regarding the outages, their emergency plans and pricing, saying they had "grossly mishandled" the weather emergency.

US President Joe Biden approved a major disaster declaration for Texas on Saturday, making federal funding available to people harmed by the storm.

All power plants were back online at the weekend and power had been restored to most homes as the weather returned to normal, but concerns still remained about water supplies, with millions of Texans being advised to boil water before using.

Houston officials said the city's water was safe to use without boiling as of Sunday.

Reuters