This is despite data showing that nearly nine in 10 are actually paying into a pension plan at work.
Official statistics reveal that 88% of eligible employees are saving into an occupational pension scheme.
Outsourced pension admin firm EQ says its study suggests that auto-enrolment has been a significant success but engagement with employees is low.
Research was conducted with over 2,000 adults and found that only 48% of the UK’s full-time workers believed they were saving into a pension.
Duncan Watson, CEO of EQ’s pension business, said the results demonstrated a need for greater pension saver engagement to “cement” the success of auto-enrolment.
He said: “Auto-enrolment has revolutionised pension saving for millions of Britons who are now participating in their workplace scheme due to the opt-out system now in place. It is evident, however, that pension saving is still not on the radar of many people, even if they are actually making contributions to their retirement fund.
“The first step of the process is now complete – now focus should shift to encouraging employees to engage with the pension saving journey, increase awareness of the importance of increasing their contribution rates and maximising employer contributions.”
He said without better engagement there was a risk workers could lost track of their workplace pensions.
Previous EQ analysis of ONS figures founds that preserved capital in defined contribution pensions has surged since the advent of auto-enrolment, rising from £139bn in 2012-14 to £291bn in 2016-18.
Mr Watson says he believes the Pensions Dashboard will help to ensure workers have a closer connection with their savings.