Personal injury lawyers face paying 60 per cent more on their Solicitors Indemnity Fund (SIF) contributions from September.
The rise - estimated at u10,000 per PI firm per year - follows a change in the way their risk assessments are calculated by SIF.
The previous risk calculations were based on historical information, explains a SIF spokeswoman.
However, it has now switched to a new system of calculation based on the future projection of claims made by lawyers.
That system will start on 1 September. The SIF spokeswoman explains: "Personal injury losses have decreased but the overall losses decreased by much more so, as a proportion of the whole, the actual claims have gone up."
Ian Walker, president of the Association of Personal Injury Lawyers (Apil), says: "We are extremely concerned.
"We understand that if other areas show a much better claim record then the load has to be distributed, but is does seem that personal injury has been chosen for an increase that is out of all proportion."
He adds: "We think that firms that practise 100 per cent personal injury are going to have to pay an extra u10,000 a year."
The spokeswoman confirms: "Thirty-one firms do 100 per cent personal injury and [contributions] will be put up by 58 per cent."