Cost-of-living payments worth hundreds of pounds will arrive in millions of people's accounts from Wednesday.
More than 11 million pensioners will receive regular winter fuel payments boosted by an extra £300 this year.
A million people on tax credits can also expect to see a second cost-of-living payment arrive in their bank accounts over the next week.
However, recipients were warned to look out for fraudsters who may exploit the situation.
Anyone contacting people directly about cost-of-living payments could be con artists attempting to steal personal details, the tax authority is warning.
The latest payments are in addition to the £400 being distributed to every household, and the Energy Price Guarantee, which caps the price that suppliers can charge.
"We want to do everything we can to support pensioners who are often the most exposed to higher costs," said Work and Pensions Secretary Mel Stride.
"As we deal with the impact of Putin's illegal war in Ukraine and the aftermath of the pandemic, we will continue to stand by the most vulnerable, with further cost-of-living payments coming next year," he added.
For the vast majority of pensioners, the extra support with winter energy bills will be automatically paid into their accounts within the next two months. However people who do not receive benefits or the state pension will need to make a claim.
The money will appear on bank statements with the payment reference starting with the customer's national Insurance number followed by 'DWP WFP' for people in Great Britain, or 'DFC WFP' for people in Northern Ireland.
About one million people in receipt of tax credits will receive their second cost-of-living support payment of £324, also aimed at helping with higher energy bills.
Another seven million people on low incomes who receive certain benefits were given cost-of-living support in recent weeks.
A range of cost-of-living payments are being provided to eligible households by the government during the second half of the year, on top of the £400 discount for all billpayers.
Those on low-incomes and receiving various benefits are being paid £650 in two instalments. The second payment went out to the vast majority of them in recent weeks.
People who qualify through their tax credits award, rather than through other benefits, received their first payment between 2 and 7 September. The payment being rolled out now is their second.
The latest payment reference in their account will be "HMRC COLS".
HM Revenue and Customs (HMRC), which administers tax credits and this specific payment, has warned everyone to be aware of fraudsters taking the opportunity it provides to steal personal details.
It warned that anyone contacting you out of the blue about cost-of-living payments saying they are from HMRC, could be part of a scam.
HMRC said it would never ask for bank details by text message or email.
Further cost-of-living payments will be sent out next year, including:
The government, which made the announcement during the Autumn Statement, said it would publish information about the timing of the payments in due course.
What the Autumn Statement means for you
Who can get the latest cost-of-living payment?
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