Non-Payment of wages by contractor - mode of payment for principal employer? By Cash or deposit in their bank account?

If contractor fails to pay wages of the workers, then it becomes the responsibility of principal employer to arrange for the payment of wages of contractual labours.
What should be the mode of payment of wages to contractual workers? By Cash or deposit in their bank account?

Ideally, it should be through ban. However, if by chance account is not available, to such workers you can pay in cash and take their signatures as proof of payment.
Then proceed to recover from the contractor, if he is still working with your concern or else wipe off your responsibility by discharging the payment on his behalf for that particular period.

It is mandatory to pay wages to contract labour through Bank only
R R Kapoor Vadodara

The Wages should be paid with corresponding deposit to EPF and ESIC Authorities. Then only the compliance is 100 percent.