Kia Ora – The unused portion of the subsidy should be used to pay to other affected staff members in the first instance.
Where there are no other employees, the excess funds should be held and returned to MSD via the following process:
Email COVID19subsidy_overpayment@msd.govt.nz and include the following details:
New Zealand Business Number (NZBN), if you have one
And advise the amount overpaid and the reason to pay it back.
I agree with Fiona that before you email MSD, give them a call to confirm.
Note that wage subsidy funds cannot be used for anything other than the payment of wages to the employees named in your application.
All the best