This is an awkward situation not envisaged by the wage subsidy scheme, which was really introduced to save jobs.
I suppose one of the key questions to answer was did you make the redundancies in light of the prospective closedown not knowing what the govt. might do to support business. If the answer to that question is yes, then I think there is justification by consent to terminate the redundancy, employee willing, but before doing so, I would suggest approaching WINZ for an answer before discussing with employees.
In theory, the employees will be entitled to claim income support etc, so their short term financial position might be off-set by welfare / income support – although cashflow might be impaired.
I presume you paid the 2 week notice you referred to already otherwise you are still clearly obliged to pay.