One in six adults is at risk of being tipped into a debt crisis, according to the Money Advice Service (MAS).
Research among over 26,000 people from across the UK found 15.4% say they regularly miss bill repayments or feel overwhelmed by their debts.
The MAS, an independent body set up by government to offer money tips, is urging people to look out for warning signs that their friends or family members could be experiencing problem debt.
Its findings suggest a "worrying" 10% of the population could be suffering in silence with serious money problems, with young adults, people who rent their homes, large families and single parents at particular risk.
The MAS said debt problems can often be hard to spot, as they can often build up over time so people may not be fully aware of the extent of the financial difficulty until it becomes a crisis.
Those experiencing problem debt may also try to hide the symptoms, due to embarrassment, to protect their friends or family or because they do not want to face up to it.
The MAS said there are however, physical, emotional and behavioural symptoms which can sometimes be linked to financial difficulties, particularly if someone has had debt problems previously. These could include:
:: A recent life event, for example having a baby, being made redundant, illness, divorce or a death in the family.
:: Signs that someone is living beyond their means or over-spending - they always seem to have the latest "must have" items although they do not have the income to cover this.
:: Someone seem anxious, withdrawn or depressed, they have reduced time socialising, they are avoiding friends.
:: They may seem more secretive - starting to hide issues and avoiding talking about finances.
:: They have changed their spending habits - either reducing spending or over-spending.
:: They seem tired or are having trouble sleeping.
:: Their weight has changed suddenly - either increasing or decreasing.
The MAS said that when starting a conversation with someone thought to have problem debt, it is generally a good idea to try to keep language "neutral and non-judgmental".
Sheila Wheeler, director of debt advice at the MAS, said: "With one in six people in the UK at risk of a debt crisis, there is a high chance that someone close to us may be struggling with money troubles. We are calling on friends and family to watch out for the signs someone might need help and to support them to access free debt advice as soon as possible.
"For people who are experiencing financial difficulties, we want you to know that help is available and you do not need to suffer alone. Friends and family will want to help and support you.
"Free debt advice is available now and will help support you in getting your finances back on track before your money worries become a bigger issue."