Borough Citizens Advice boss Ian Thompson fears the whirlwind will come from debt recovery firms restarting their pursuit of claims and benefits chiefs resuming challenges of claims awards.
Both measures have been put on hold by the Government since the start of the pandemic to support households.
But Mr Thompson said thousands of people living on or just above the breadline, and receiving help, will be hammered when pre-Covid rules are reapplied.
And he believes people in employment, especially those being supported by the national furlough scheme, are also at serious risk.
He warns many employees could be cast aside by businesses once the 80% furlough support grant is axed, forcing them onto benefits.
Mr Thompson, chief executive of Citizens Advice in South Tyneside, said the impact of the coronavirus pandemic and Brexit could have an impact in the early months of this year.
He said: “It really is a perfect storm.
“At some point the Department for Work and Pensions will lift its restrictions on medical testing, and we can expect a huge spike in the challenges we have to bring when that happens.
“Debt recovery was also suspended, and people haven’t been getting pursued, but they will be.
“These expected changes will affect people on low incomes and benefits, and people in employment may be pushed over the edge.
“This will have a huge effect on the local economy and bring great stress and anxiety to people, including around jobs.
“People who are in work are being supported but are getting only 80% of their wages but need 100% to survive.
“In the past three years, we have seen a large shift in debt from consumer credit, such as pay-day loans, to personal debt, such as not being able to pay rent and council tax.
“More people are struggling to pay their rent and keep a roof over their heads.”
He added: ‘The outlook for next year is bleak, I’m not sure Citizens Advice will be able to cope with the demand for support I expect to come our way – it may outstrip our capacity.
“I worry that without access to free support and advice around debt and other issues, there will be a big increase in repossessions and increased issues around mental health and anxiety.
“My concerns are not just around Covid. There will also be the impact of Brexit, and when these combine, the effects are going to be devastating to many people in South Tyneside.”
Mr Thompson said the agency saw a spike of 79% in requests for help around Universal Credit in the early months of the pandemic.
There was a 39% increase in employment advice, a 33% for housing guidance, and a 73% jump in support around relationships.
Over 9,000 clients sought support in the year to March 31, and 6,353 have been helped in the months since.