Up to 1.6 million pensioners in the UK are failing to claim pension credits they are entitled to, according to official figures.

The Department for Work and Pensions (DWP) has published a new report which shows that £2.8 billion of the means-tested credit, which is used to top up pensioners' weekly income, is going unclaimed each year.

With pension credit worth around £33 a week, the DWP estimates that between 1.2 million and 1.6 million of the country's poorest retirees are missing out on vital funds.

Michelle Mitchell, charity director general of Age UK, expressed her disappointment at the figures and called on the government to promote awareness of benefits.

"There are still 1.8 million people in later life living in poverty and claiming pension credit can make a huge difference to someone's income and quality of life," she said.

"The government needs to start an awareness programme and move more towards a system where the DWP pay entitlements rather than an individual having to work their way through the benefits maze."

The report also showed that up to 3.2 million people are missing out on up to £2.4 billion in council tax benefit and up to 620,000 people are failing to claim up to £2 billion in income support, and employment and support allowance.