On Monday in Wellington, Ms Ardern said the government would conduct a "check-in" on the plans in early January, citing the Omicron variant.

"It makes sense to ensure we assess the next move against all the latest information and advice we have, including the relative effectiveness of the vaccine against the Omicron variant," she said.

The Omicron variant is yet to land in New Zealand, and Ms Ardern's government is keen to keep it out while scientists assess how transmissible and deadly it may be.

However, Ms Ardern's announcement runs contrary to firm commitments the government had given to the date, and is likely to infuriate those waiting for the border opening.

Under the plan, announced last month, Australian-based Kiwis would be allowed into New Zealand without needing to quarantine from January 17.

Instead, they'd be able to self-isolate on arrival for a week, with those further abroad allowed to do similarly as of February 14.

Finally, non-New Zealanders would be allowed in under the same rules from April 30, which would effectively mark the end of the hard border.

"We haven't changed those plans. We haven't changed the timelines we've set out," Ms Ardern stressed.

"But it does make sense for us to have that check-in to make sure we're still comfortable."

The question of when New Zealand will eventually abandon the self-isolation provision is also a matter of sharp debate.

Last week, Tourism Minister Stuart Nash told an industry roundtable they should prepare for the self-isolation requirement to stay in place for all of 2022.

In an interview with AAP, Ms Ardern said she would be open to moving sooner, but business should be prepared for a year of self-isolation requirements.

"Let's prepare and plan for those difficult scenarios, but then have the flexibility to move (earlier)," Ms Ardern said.

The NZ government is prioritising ditching domestic restrictions over freer international borders, hoping to keep cases to a manageable level for its health system.

On Wednesday, border restrictions around Auckland - since August the centre of a Delta outbreak - will be removed.

The government believes once the Auckland border is opened, the virus will eventually spread to other parts of New Zealand, and opening up internationally at the same time creates an unacceptably high risk of further outbreaks.

Tourism Industry Aotearoa chief executive Chris Roberts said keeping the soft border will cost the economy $NZ16 billion ($A15.2 billion) in lost earnings.

"Australian tourism is grateful they don't have New Zealand as a competitor ... instead of going to New Zealand, (tourists) could go to Canada or Australia or the USA and not do self-isolation," he told AAP.

"It's going to be an intensely competitive market - it already is - and New Zealand is going to start at the back of the field."

Mr Roberts has called on the government to re-start a trans-Tasman bubble-style arrangement at some stage in 2022.

Ms Ardern is hearing the calls, but does not want a similar outcome to the previous bubble, which was canned after three difficult months.

"What we want to do is not move back and forward. Lots of countries who took off restrictions are putting them back on," she said.

Those upset with New Zealand's border settings continue to ramp up pressure on the government.

Lobby group Grounded Kiwis are presenting a petition at parliament on Tuesday, signed by 23,000 people who see the border rules as unfair.

Australian Associated Press