Three-quarters of women do not know what pension to expect from the state and most lack confidence when making retirement decisions, a report has found.
The Pensions Advisory Service, which carried out research among 1,000 women, found that many "do not know where they stand" when it comes to pensions and several thought that changes were being made too swiftly for them to do much to alter their plans.
Women often weave paid work around their caring responsibilities and tend to be more heavily reliant on the state pension for their retirement income than men.
But just 26% of women surveyed knew how much they would get from the state in retirement, one third (36%) did not know when their state pension would be paid and 57% did not know if there was a shortfall in their National Insurance (NI) record, the report found.
Meanwhile, 71% of those surveyed also said they did not not feel confident about making decisions when saving for retirement.
A further 76% of women did not believe they would have enough income to be financially comfortable once stopping work.
Michelle Cracknell, chief executive of the Pensions Advisory Service said: "The odds of women being able to provide for a comfortable retirement are stacked against them from the start.
"The price they pay is an incomplete state pension in their own right and not much, if any, private pension to add to it."
The single-tier pension - which will affect around 40 million people of working age when it comes into force - will run alongside the Government's landmark plans to automatically enrol people into workplace pensions in the coming years, to encourage confidence in retirement saving.
The Government previously confirmed plans to bring forward the start date for the single-tier pension to April 2016.
Ultimately, the reforms are intended to reduce people's reliance on means-tested benefits and give more certainty about the value of saving into a private pension scheme.
The single-tier pension will be based on individual qualification, so someone will not be able to inherit or derive rights to the single-tier pension of their spouse.
But if someone has contributions or credits on their National Insurance record under the current state pension scheme, there will be transitional protection.
The flat-rate amount will be based on 35 qualifying years of NI contributions and someone with less than this can still get a pro-rata amount.
The Work and Pensions Committee said in a report last April that the success of the new simple flat-rate state pension hinged on the Government helping people to understand how they would be affected ''as soon as possible''.
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The Pensions Advisory Service's Women and Pensions report found that over half (57%) of women were unaware of any shortfalls in their NI records which, if known, would help them to build up their level of state pension.
More than half (54%) of women surveyed have not made any changes to their retirement plans in the light of changes to state pension age, with only one in 20 (5%) actively planning to extend their working lifetime.
The Pensions Advisory Service is an independent body which offers a free service to the public and sits under the stewardship of the Department for Work and Pensions (DWP).
As part of the report, the Service plans to raise awareness about accessing information about state and private pensions and making up pension shortfalls.
Ms Cracknell continued: "There are a number of simple actions which many can take, such as checking National Insurance contributions, opting into a workplace pension and claiming tax reliefs which can help with their pensions."
The report also found the women surveyed have a "good knowledge" of automatic enrolment, indicating that the DWP has been successful in raising awareness of the scheme.
When asked what they would advise a younger woman starting employment and being automatically enrolled to do, the "near universal" response was to encourage women to stay in and contribute as much as they could for as long as they could.
Three-fifths (61%) of women were aware of how much their private pension plan would pay in retirement, or knew where to obtain estimates of this.
Ros Altmann, an independent pensions expert and former Downing Street adviser, said: "For years, women have been the second-class citizens in both state and private pensions. This particularly affects women already in their late 50s or older.
"Women have shorter working careers than men, so they have less years during which they can save for a pension or contribute to National Insurance and women also earn less than men when they are working, once again leaving them with less chance to save for a pension and leaving them with lower state pensions as they lose out on the earnings-related element of the system."
Dr Altmann urged the Department for Work and Pensions to ensure it writes to all women to let them know what their state pension entitlement is and how to buy extra years of contributions if they can.
She said: "Any woman who is unsure about her situation should contact the Pensions Advisory Service national helpline to make sure they are better informed and can plan as best they can."
Pensions Minister Steve Webb said: "Our reforms to the state pension will give people more certainty about what they will get, benefiting women and carers in particular. And automatic enrolment is already helping many more women to save in a workplace pension.
"It is encouraging that this survey shows more women are more optimistic about pensions."