The Law Society has told regulators that solicitors should not be expected to pay for losses incurred by uninsured firms.
The Solicitors Regulation Authority proposed last week that payments would be taken out of the Compensation Fund from later this year. The fund, paid for by contributions from law firms, currently covers claims made as a result of a solicitor's dishonesty.
The SRA's proposal is part of wide-ranging changes to dealing with firms that cannot secure professional indemnity insurance.
The Society has already agreed the profession should share with insurers the cost of funding firms that go into the assigned risks pool.
But the Society says it is 'disappointing' that further costs could be added to the Compensation Fund and has urged the Legal Services Board to overrule the decision.
Chief executive Desmond Hudson said: 'The provision for insurers collectively to meet the losses from uninsured firms, as they do in motor insurance, is a fundamental part of the arrangements for solicitors' PII. The SRA's proposal to transfer cover for uninsured firms to the Compensation Fund would be a costly burden on the profession.'
Currently, cover for uninsured firms is provided through collective arrangements funded by qualifying insurers. The Law Society said a change in this policy would punish firms that have complied with the rules and paid for their own insurance already.
The SRA said it has consulted on the new plans for more than three months. The SRA board will consider the proposals on 16 May.