One in four householders believe they will still be paying off their mortgage or paying rent when they retire, according to research from insurer Aviva.
The belief is most prevalent among women in the 35-44 year age category.
However, a surprisingly large proportion of people aged over 55 - about a fifth - said they expect to be still making mortgage repayments or paying rent in retirement.
The survey of 1,400 people was carried out by iReach Insights on behalf of Aviva in August.
If the findings are applied to the wider population, it amounts to over 780,000 people who would expect to still be paying either their mortgage or rent in retirement.
44% of respondents said they would most likely take up a job - either full- or part-time - to supplement their income in retirement.
One in ten said they would be seeking a full-time job.
Of those who still expect to still have major financial commitments in retirement, about a fifth said they would have to depend on State support to fund the payments.
Another fifth said they plan to use their savings or investment income with 16% saying they would fund it using their retirement lump sum.
"A Central Bank of Ireland report published in July reported that the over-60's currently represent a quarter of all cases in long-term mortgage arrears. The reality is that this figure is likely to increase further as will the incidents of people struggling financially in retirement unless people begin to save for their retirement earlier and take advantage of the tax benefits that are available to pension savers," Stephen Rice of Aviva said.
"Our research findings highlight some very real societal issues that need to be debated at policy and governmental level if we are to avoid people living in poverty in retirement or being forced to work well beyond their normal retirement age," he added.