"Working for longer ... will play an important part in helping people to save to meet their retirement aspirations," Johnson told parliament.
"This strategy establishes a long-term aspiration of moving towards an employment rate equivalent to 80 percent of the working age population," he said. Despite an employment record that is the envy of Europe, Britain faces a mushrooming bill for pension provision, as the population ages and people live longer.
Latest figures put British unemployment at 4.7 percent of the workforce in December - the euro zone jobless rate was 8.9 percent for the same month.
But the British data also showed only 74.8 percent of 16-to-64-year-olds were actually in employment - millions have either retired early, chosen to stay at home or are on non-employment welfare schemes such as incapacity benefit.
Johnson said that benefit, paid to nearly three million sick and disabled people, would be overhauled to stop it acting as a disincentive to return to work.
"We know that perhaps a million people claiming incapacity benefit say they would like to work if they were given sufficient help and support" he said.
Officials admit firm pensions proposals will not be announced until after May's expected election, so controversial could be the measures needed.
The government's pensions adviser, Adair Turner, has already set out four options - allow the number of poor pensioners to grow, raise taxes, increase private saving, or increase the average retirement age.
But Johnson would not be drawn on detail.
With an ageing population living longer, a stock market still well below its peak of a few years ago and with complex tax changes having robbed pension funds of billions of pounds, Britain's pensions system is creaking.