Disabled Australians could be forced to wait up to a year for their disability support claims as the government's crackdown on the pension clogs the system with thousands of medical examinations.

Claimants are being told there are not enough doctors on Centrelink's books to perform all the Disability Medical Assessments ordered under the Coalition's disability support pension policy, despite a private-sector operation being hired to carry out the work for $21 million a year.

Claimants are being told there are not enough doctors on Centrelink's books to perform all the Disability Medical Assessments.

But the giant Department of Human Services denies there is any problem processing the assessments, says that the reports of the 12-month processing times are not correct, and that claims for the pension can be complex and will take as long as they take.