It is estimated that more than 3,000 Oldham households are cut off from the pension credit amid a cost of living crisis.
The Greater Manchester Combined Authority and charity Independent Age are asking people to check their eligibility for support, which averages £63.54 a week for those already claiming in the area.
The pension credit is a supplement to the state pension of those who are below a certain income threshold.
Over the course of a year, an average of £63.54 per week comes to a significant total of £3,304.08.
But based on adoption across the UK, it is estimated that more than 3,000 households in Oldham are missing out when they need it most.
Simon Hewett-Avison, director of services at Independent Age, said: “With the cost of living crisis set to worsen later in the year, it is essential that people of retirement age State check whether they are entitled to the pension credit.
“The support you might be entitled to is sitting in a pot and not being claimed.
“It only takes a few minutes on the phone to check if you’re eligible and the average applicant gets an extra £3,300 a year.”
Those who receive pension credit are entitled to a range of benefits from free NHS dental care to a free TV license.
They are also eligible for government aid of £650 towards the cost of living, although this must be claimed by August 18.
Mr Hewett-Avision added: “Even if you’re only entitled to an extra £1 a week, then you can unlock a range of benefits worth up to £7,000 a year.
“We know from our research that some older people make severe budget cuts just to survive.
“We’ve heard of people cutting up fresh fruit and vegetables in their store, not seeing friends because of the cost of a cup of tea, or delaying getting a prescription.
“Access to pension credit can help with these day-to-day expenses.”
For more information and a full list of benefits, go to Independentage.org/get-advice/money/benefits/pension-credit.