Sudbury Fun Run organisers are calling for help to avoid a bill of more than £4,000 for road safety measures.
Road closures and safety management needed for the annual five-mile run were formerly provided by police, who no longer offer the service.
The event, which is expected to attract more than 500 runners and walkers on March 29, raised £6,000 last year for Helping Hands and St Nicholas Hospice Care.
It now faces losing the majority of its proceeds to a road management company to fulfil the legal requirements.
Jonathan Price, one of the fun run’s organisers, said: “It would be tragic if much of this money was lost to red tape.
“We can only hope people with the necessary qualifications will come forward to support us or some other local organisation or business can help meet some of the cost.”
Less than 150 places are left for this year’s run, which will raise funds for five Sudbury charities. Anyone wanting to help can call Mr Price on 01787 880796, or go to www.sudburyfunrun.co.uk to sign up.