The research showed awareness is poor among the scheme's target audience: lower-paid workers in small businesses. The report revealed the larger the organisation the respondents work for, and the higher the salary, the greater the awareness, even though automatic-enrolment is largely designed for small employers and the type of people without a pension scheme.
Only a third of employees on an income of under £20,000 were aware of the changes, the survey found.
Lynn Graves, Scottish Widdows head of business development, told HR magazine: "While it is encouraging that 40% of UK employees have already indicated that they intend to stay automatically enrolled into their employers' pension scheme, it is clear that substantially more work must still be done. Increasing awareness of auto-enrolment among the one in five (18%) who are still undecided is crucial.
"As an industry, we must encourage people to save more towards their retirement and this is a challenge for government, employers and providers," she added.
Graves said: "Auto-enrolment has the potential to engage parts of the population we have collectively failed to reach in the past, but there still remains a huge gap in awareness."
The survey said the media has a massive role to play in awareness, with 61% of people surveyed citing the media as to how they knew about the scheme. Only 16% were aware of the scheme through their employer.
Tim Jones, chief executive of National Employment Savings Trust (NEST), said: "The information workers get from their employers will also play an important role in aiding understanding.
Communications in the workplace will make people start to take notice and people tend to listen to the views of others they work with."
Those who were aware of auto-enrolment were overwhelmingly in favour of it. Only 11% plan to opt out. For 32%, the main reason they give is they can't afford the monthly contributions.
The Scottish Widows UK Workplace Pensions Report was based on an online sample of 5,200 UK adults earlier this year.