People on state pension have been warned that they could be missing out on more than £1,000 a month, giving them a weekly boost of as much as £279.
Pension Credit gives individuals extra money to help with living costs if they are over State Pension age but on a low income.
It can also help with housing costs such as ground rent or service charges.
The Government offers those on Pension Credit other help such as cold weather payments, a free TV licence and help with NHS dental treatment.
The Government has a surplus of £1.7billion from unclaimed pension credit funding.
Nick Ansell
More than 1.4 million pensioners are currently on Pension Credit but an estimated 850,000 people
Recent statistics have shown that around 850,000 people in the UK could be eligible for Pension Credit but have not applied.
This has left a surplus of £1.7billion with the Government.
Those on the scheme could receive up to £279 a week as well as becoming eligible for a number of other free services.
Pensioners on a low income who are single receive £182.60 a week.
Those who have a spouse or civil partner receive £278.
In his autumn statement, Chancellor Jeremy Hunt confirmed the state pension, pension credit and benefits would have been uprated in line with inflation – a 10.1 per cent increase from April.
This would increase single people’s income to £201 a week and couple’s income to £305.
The scheme could supply pensioners with an additional £279 a week.
Yui Mok
Group communications director at Just Group, Stephen Lowe, said: “The human story to this is the hundreds of thousands of people who are struggling to make ends meet who may not realise financial help is available or do not know how to navigate the system."
“Pensioners are facing a steep increase in inflation which could rise to over seven percent this year according to the Bank of England – that would outstrip by some margin the one-off ‘double lock’ state pension increase of 3.1 percent that is coming in April," he continued, speaking to the Express.
“As the cost of living crisis starts to bite, and with pensioners heavily impacted by rocketing energy bills, it is more important than ever that people who may be struggling for income are aware of the benefits available to them and how they can claim.
“There are a range of free resources to help people and families can use a variety of online resources to check if they suspect elderly relatives may be missing out on valuable help.”
Those who want to claim Pension Credit can visit the Government's website where a range of calculators and advice are available to help.