A total of 1.4 million have already fallen behind, with almost a million people resorting to high-interest 'pay day' loans to make ends meet.
"It's shocking to think that so many families will be starting the New Year with a huge weight hanging over them, trapped in a daily struggle to keep their home," said the charity's chief executive Campbell Robb.
"Payday loans may seem like a quick fix, but the huge interest charges mean things can quickly spiral out of control.
"It's vital that anyone who's having difficulty paying their rent or mortgage gets advice now. Don't wait until things reach breaking point later in the year - it could leave your family's home at risk."
Mother-of-two Mandy Buxton from West Sussex has found it impossible to balance the books over the past couple of years and opted to take out pay day loans to get by.
It is a decision she now bitterly regrets, as she faces up to having to leave her rented property.
"I got to the point where after I had paid off the loan I had 50p left and that had to last me the month," she told Sky News.
"I realised I couldn't carry on the way I was so I had to say to my boss that I wouldn't be coming back to work because I didn't have the money to get there and back.
"If you have to take a few days off work because one of your children is ill or there is a problem it puts you in a situation where you just can't pay the bills."
But with interest rates at an historic low, how will people cope in the next few years if and when rates go back to where they were before the recession began in 2008?
Mortgage expert Paula John says many people will eventually start moving towards fixed-rate mortgages.
"For hundreds of thousands of families it's only the very low mortgage rates that have been keeping the wolves from the door," she told Sky News.
"Many UK households have really been struggling over the past few years and if rates were to go up it would be a real concern.
"I think people are more financially aware now than they were a few years back and what we will see is a mass movement towards fixed-rate mortgages."
Shelter said it is seeing a rise in demand for its services and pointed out that people are finding "there is little left of the housing safety net that was once there to help them get back on their feet".
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