Of those with disabilities, over half (53%) said they had been deterred from checking or claiming potential benefits entitlements because they did not think they would be eligible.
And one in four feel that recent welfare benefit changes have made it too difficult to apply.
As a result, nearly two-thirds (65%) have not checked what welfare benefits they could be entitled to within the last year.
More than two in five of people with disabilities, who don’t currently claim benefits, said they would have to cut back on gas, electricity and other essentials if their income dropped; and nearly two in four would resort to cutting back on food.
The research is released as Turn2us launches its 2016 Benefits Awareness Campaign to help more people in financial hardship to access the welfare support available to them.
The charity is urging anyone in need to use its free and confidential Benefits Calculator at Turn2us.org.uk to see what they could be entitled to and how to make a claim.
The website also features information on benefits and other help for a range of different circumstances.
Simon Hopkins, chief executive of Turn2us, said: “Shockingly around £15bn in welfare support still goes unclaimed every year, and as our findings show, people often feel that benefits simply aren’t for them.
“We want to show that financial hardship can happen for many different reasons and could affect anyone at any time in their lives.
“Welfare benefits exist to provide a vital source of support for people in need, and as our research highlights, these can make a positive difference in paying for basic life essentials.
“We would urge anyone struggling to visit our website today to check what support could be available.”