Rooms have been sitting empty in managed isolation hotels, because people are 'panic-booking' multiple allocation vouchers they don't need.
MBIE says since November up to 16 rooms have been empty each day due to people who've booked multiple vouchers, or have flights but no voucher, or have vouchers - but don't board their flights.
It's asking people to cancel vouchers they don't need, and says it strongly discourages people reserving more than one voucher without flights booked.
Immigration lawyer Richard Small says the system has become overrun with desperate people who are booking everything that they can.
He says any extra bookings for managed isolation and quarantine should be cancelled, but that is not happening.