The research included some people who had already retired and said their savings were running out faster than expected because the cost of living was higher than they had realised.
Earlier this week the commission released data showing Kiwis are severely underestimating how much they will need to buy groceries over 30 years in retirement.
More than 70 per cent of the people surveyed thought it would be less than $250k for a couple - a figure based on research by Massey University on the real cost of living in retirement.
The commission's over 50s found many said they had not saved enough for retirement and the only solution was to work longer.
We will put it to financial adviser Hannah McQueen as part of our live chat online on Friday at 12noon.
One in five Kiwis is already working beyond the age of 65 and that number is expected to grow.
Some people said they did not know how they would cope in retirement.
"I am renting. My rent costs me half my wages. It is a struggle to exist now, and I am working 30 hours a week in the school term. I will be even worse off with the pension.
"I will need to find a cheaper rental, which I have already tried to find. How will I afford to eat? Live? It is hard enough now, and I live alone," one person commented.
Another said: "We have modest superannuation... no mortgage and know that we will still have little to spare once we have dealt with rates, health, insurance, household and car insurance, food escalating power costs and basic household maintenance."
We don't smoke, we don't drink, we don't gamble and we don't take holidays.... We know we are better off than many but retirement is not going to be in any way pleasant.
Many of those who identified with being vulnerable were renting or had large mortgages, other debts, no savings and frequently they or their partners had health issues.
Being single was also a challenge.
"I'm in my fifties. I have KiwiSaver. I can't afford to put a higher rate in my fund as I have a mortgage. It does concern me. I won't have anyone to rely on," one respondent said.
The need to support children, including adult offspring who were unemployed, had health issues or financial challenges was a commonly identified barrier to saving for retirement.
Retirement Commissioner Diane Maxwell said people were living for longer in retirement and that was putting more financial pressure on them.
"We've got to live on a fixed income for a lot longer than our grandparents did."
Maxwell said lots of people were making plans to manage their later years but she was concerned for those who weren't able to.
The commission is undertaking its three yearly review of retirement income policy this year and will report back to government on its findings by the end of the year.
"Our review will consider what can be done to support those people."
