These 'under-savers' are expected to have pension incomes below the target levels suggested by the Pensions Commission in 2004.
Minister for pensions, Steve Webb (pictured) said: "This is a very large group of people who will face a big drop in their living standards on retirement if they do not take action now.
"And this is not just a problem for those on lower wages – those on high incomes are just as much at risk of having a lower standard of living in retirement if they do not take this seriously.
"We have to make it easy for people to save, in confidence, knowing that they are putting enough away to have a comfortable retirement.
"Our reforms to the state pension and the start of automatic enrolment into workplace pensions will help people do this.
"A simple flat-rate state pension above the basic level of the means test will bring much needed clarity and simplicity to the pension system.
"It will provide the foundation needed to support automatic enrolment into workplace pensions, helping to ensure people can save for their retirement with confidence."
