The seven-day grace period for Kiwis returning from Australia will finish at 11.59pm tomorrow, the Government has announced.
After that, travellers will need to get an MIQ voucher to be able to fly to New Zealand - and they are all currently taken until the end of November.
Prime Minister Jacinda Ardern said last week that the seven-day window might be extended depending on demand, but that demand has now dried up.
"Cancellations now outweigh new bookings and around 3000 seats [are] still available," acting Covid-19 Response Minister Ayesha Verrall said.
"Extra flights have been put on where required, for example from Brisbane and Melbourne, and extra capacity has opened up on flights from Perth as people have cancelled their flights. Travellers also have the option to transit via other airports in Australia.
"We believe most eligible travellers who wish to come back have taken the necessary steps to do so and we're urging those who might still be deciding to act immediately."
Verrall also announced an extra 500 MIQ rooms for travellers returning from New South Wales, the epicentre of the current outbreak in Australia.
These travellers have to spend 14 days in MIQ and don't need MIQ vouchers, as one is assigned to their flight seat.
The extra 500 MIQ rooms are for passengers flying between August 9 and 22.
Passengers are asked to use a "registration of interest" process using a form on the Government's Covid-19 website.
The registration process will open from 10am tomorrow and close at 2pm on Tuesday, August 3.
Less than half of the available seats have been occupied on flights from Australia to New Zealand.
Kiwis citizens and residents in Australia but not in NSW can still use the last day of the grace period to return to New Zealand without an MIQ stay.
Those who fly in from Victoria will need to isolate at home until a day three negative test.
All returning passengers from Australia except those from NSW will need a negative pre-departure test, without which they will not be allowed to board their flight.
An estimated 21,000 Kiwis had travelled to Australia without returning since the transtasman bubble opened, prompting questions last week whether seven days was long enough for travellers to return home.
The bubble closed last week as the Government decided it was too risky, given the Delta variant was present in several Australia states.
NSW recorded more than 200 new daily cases today - the most in the current outbreak despite weeks of being in lockdown.
Director-General Ashley Bloomfield said at the time that the overall risk was low but rising, while Ardern said the risk of "seepage" across state borders was enough to warrant closing the bubble for at least eight weeks.
The decision was supported by opposition parties as well as Business NZ and Tourism Industry Aotearoa, which said the losses to the sector would be minimal seeing as the bubble with NSW and Victoria had already been paused.