Some 43 per cent said they could not afford any additional payments on top of the mortgage interest.
The study found that only 21 per cent of investment-only mortgages have plans in place to use other investments to pay off their mortgage capital.
Mike Rogers, chief executive of the Liverpool Victoria Group, said people should "serious consider" regularly investing to pay off the mortgage "at the end of the term".
"A previously booming property market led many people to bank on being able sell their home, use the proceeds to pay off the mortgage, and still have enough left to buy another home," he added.
"However, this strategy may have been overturned by current and predicted future falls in property prices."
Recent research by Halifax found that 38 per cent of property owners plan to become more environmentally conscious in the hope of cutting costs in their homes.
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