Modi alleged that the scam occurred in construction of the house-cum-office of the district project manager, houses for medical officer and nursing staff and drug warehouse.
The construction work was carried out by the state agency Bihar Medical Services & Infrastructure Corporation Ltd (BMSICL) at a time when Kumar held the health portfolio after sacking the BJP ministers, he said.
An irregularity of funds between Rs 4.78 crore to Rs 8.62 crore in the projects has been detected by the Office of the Accountant General (Audit), Bihar, in its recent report, Modi told reporters while releasing the audit report.
Reiterating his demand for a CBI probe in the matter, he said Chief Minister Jitan Ram Manjhi should recommend it unless he sought to shield his predecessor.
The chief minister has rejected Modi's demand for a CBI probe in these scams saying that the state agencies were competent to do so and bring the culprits to book.