Authorities had planned on allowing fully vaccinated Kiwis based in Australia to bypass quarantine until January 17, but on Tuesday it kicked that plan down the road.

New Zealand will instead continue to require all citizens to complete hotel quarantine, known locally as MIQ, on arrival until late February.

This fresh delay is the latest frustration for those looking to head home.

Air New Zealand cancelled flights carrying 27,000 people in the wake of the announcement.

Martin Newell from the lobby group Grounded Kiwis - set up for Kiwis based overseas and similar to the Stranded Aussies group - said its inbox was full of stories of separated families and hard luck.

"There's a 77 year old person stuck in Melbourne since the (trans-Tasman) bubble burst in July, who just wants to get home," he told AAP.

"A couple in their 70s who have been caravanning are going to lose their pension because they won't be able to get home to meet the 26-week deadline."

The policy change comes despite repeated reassurances from senior ministers that border restrictions would soften on January 17.

On the policy's announcement in late November, COVID-19 Minister Chris Hipkins said the government was "very committed" to it.

The following week, Deputy Prime Minister Grant Robertson confirmed Kiwis should keep planning for the January 17 changes.

Last week, after Ms Ardern announced the January 17 opening would be subject to an early January "check-in", Mr Hipkins announced the opening was still "very likely".

Mr Newell said many Kiwis were "grief-stricken" as they trusted the self-isolation pledge.

"People are kicking themselves in the foot because they had MIQ booked in December who cancelled them because they could self-isolate in January," he said.

On Tuesday, Mr Hipkins apologised for the change.

"I'm sorry we have not been able to meet that particular deadline," he said.

"One of the realities is that COVID continues to throw up new challenges for us ... that means while we can work to provide certainty we can't always give people certainty."

The tough border settings are prompting a legal challenge, given the Bill of Rights gives citizens a right to enter New Zealand.

More than 1100 donors have contributed over $150,000 into a crowdfunding effort, leaving the campaign around $20,000 shy of its goal ahead of a judicial review hearing beginning January 25.

"It's an important test case for the rights of New Zealanders. What's happened in the last 24 hours shows that," Mr Newell said.

Australian Associated Press