With just three weeks before new employment regulations become law, just 10% of businesses are ready.
Law firm Osborne Clarke has warned that new laws, designed to give temporary workers the same rights as permanent employees, may not be implemented in time.
Head of employment law Nicholas Moore said: "This legislation will have a dramatic effect on employers but we anticipate that 90% will not be prepared for it."
With the finance and insurance sectors using large numbers of temps, the impact on the sector is also being underestimated, they say.
The Fixed Term Employees Regulations come into force on 1st October, and will give temps the right to the same pay, benefits and job opportunities as their permanent colleagues.
However the broking firm raised doubts over the effectiveness of the new laws. Moore added: "There are fears in the business community that the very people the regulations are meant to protect will be worst affected as companies revert to using permanent contracts in an effort to keep running costs down."
The new measures will apply only to employees, and not to apprentices, agency workers and members of the armed forces.
