Spending on the National Disability Insurance Scheme is expected to blow out to $64 billion a year in 2030, even higher than previously estimated, according to an external actuarial review commissioned by disability ministers.

The prediction of $19.2 billion higher costs over the period to the end of the decade came after the NDIS actuary concluded it was facing a rise in costs from $29.2 billion this year to $59.3 billion in 2029-30.