East Yorkshire Citizens Advice Bureau is facing a "major threat" after its funding was cut by almost half.
Redundancy notices have been issued to 33 staff members at offices in Hull, Beverley, Bridlington and Goole.
Officials described the cuts as "devastating" and said a serious review is under way into what services are able to continue.
Specialist debt caseworkers will be axed from the Hull office from the end of March.
Last year they handled more than 1,750 debt cases.
CEO Lesley Thornley said: "This is devastating news for the people of Hull.
"Our team are experienced and dedicated caseworkers who are able to help clients with complex issues such as bankruptcy, debt relief orders and court action.
"It is a false economy to cut these services at a time when independent advice has never been needed more."
Several government and other funds have cut their allocations to the CAB, resulting in a fall in funding of more than £500,000, or 42%.
The service helps more than 13,500 people each year and says most enquiries are about debt issues, with demand expected to increase due to rising unemployment.