Extending IR35 legislation to the private sector could introduce "a complex web of new rules and liabilities throughout supply chains".
Medium and large companies in the private sector will be responsible for determining the tax status of contractors from April 2020.
The Association of Chartered Certified Accountants (ACCA) has called for a one-year delay in the expansion of the legislation.
It believes the stay of execution will provide enough time to allow a full appraisal of the proposed rules and consider the best way forward.
Off-payroll rules were reformed for contractors in the public sector in April 2017 , with the aim of preventing what HMRC regards as ‘disguised employment'.
Lilly Aaron, policy manager at ACCA Europe, said:
"On the surface, this legislation aims to tackle contrived working practices that may disguise the true nature of the relationship between a worker and client.
"In practice, however, this reform could create a complex web of new rules and liabilities throughout supply chains causing confusion over employment status and where tax liabilities rest.
"There are a lot of lessons to be learned from these rules being introduced to the public sector, and it is essential we get this right the first time for the private sector to give businesses some certainty."
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