Energy firms could lose their right to cut off supplies because of debt, a House of Commons committee has warned.
Electricity and gas can be cut off, but not water
The Trade and Industry Select Committee said it would recommend a ban on disconnections if firms did not improve support to customers.
In 2003, 15,973 gas customers and 1,361 electricity customers were disconnected for non-payment of debts.
The Energy Retail Association said a new "safety net" meant no vulnerable people were cut off this winter.
There are 2.8m customers in debt to their suppliers and MPs want more help for people with financial problems.
The committee said firms must clearly demonstrate that they have taken "all practicable measures to resolve the problem earlier".
Firms also need to reduce billing errors, it said.
Electricity: 1.5 million account holders in debt
Gas: 1.3 million account holders in debt
"Unless the industry demonstrates serious commitment to and success in addressing these problems, we would recommend the government to legislate to ban disconnections of domestic fuel supply," said Martin O'Neill, chairman of the committee.
The Energy Retail Association, which represents suppliers, said the MPs' report had been trumped by a new "safety net" to protect vulnerable users, which has been introduced by the industry.
It said no vulnerable person has been disconnected this winter as a result.
Disconnections came under scrutiny in 2003, due to a public outcry over the death of a pensioner couple who were found dead in their home, 13 weeks after their gas was disconnected.
George and Gertrude Bates, who lived in South London, had become too frail and confused to cope with bill payments.
One of the issues raised at the time was whether gas and electricity companies should keep powers to disconnect customers who did not pay their bills.
In contrast to electricity and gas suppliers, water companies are no longer allowed to disconnect customers who fail to pay their bills.
The number of gas and electricity disconnections have fallen significantly from a peak in the mid 1980s.
In 1987 more than 60,000 gas customers and more than 100,000 electricity customers were disconnected.
ERA said better identification of vulnerable customers had cut disconnections.
Suppliers have also introduced prepayment methods - which are generally more expensive - but can help people on low incomes budget.
Consumer groups, however, have said that more needs to be done to protect vulnerable users.
"Companies are now on final warning to sort the mess out. That means no more disconnections of vulnerable people and no more disconnections in error." said Allan Asher, chief executive of Energywatch.