Labour MP David Parker says steps to open up the border are being put in place, but don't expect any "widespread opening" until there's a vaccine for COVID-19.
He's picking June next year for the initial rollout, though admits that's not based on any scientific advice he's had.
"My pick, for what it's worth - and I don't really know anything more than you see in the media - is that by June next year we'll have a pretty widespread vaccine going out through initially health workers, rest homes," he told The AM Show on Friday.
"People can have hope that there's light at the end of the tunnel. That's the date that I talk about, but there's no certainty."
One of the most promising vaccines, being developed by Oxford University and pharmaceutical firm AstraZeneca, ran into trouble this week when one of the participants in its phase 3 trial developed a severe neurological condition.
The trial, involving tens of thousands of people, has been halted while researchers figure out if the vaccine is to blame. The suspected condition - transverse myelitis - can be triggered by a viral infection, but experts say the AstraZeneca vaccine can't cause a viral infection because it doesn't use a live version of the virus.
"The formulation of the AstraZeneca vaccine involves a platform not previously used in an approved vaccine, so caution is required to interpret if an unexpected immune stimulation gave rise to the inflammatory spinal disorder experienced by the trial participant," said Roger Lord, researcher at the Prince Charles Hospital in Brisbane.
It's also not known yet if the affected person even got the experimental vaccine - they may have been part of the control group.
"In large clinical trials, illnesses will happen by chance and must be independently reviewed," AstraZeneca said in a statement.
Oksana Pyzik, public health expert at University College London, told The AM Show on Thursday there are several vaccines being developed, each with only a small chance of success, so even if this one fails or is significantly delayed, it's not a huge setback in the fight against COVID-19.
"This happens frequently in trials, and it's a good thing the safety measures are being followed."
University of Auckland vaccinologist Helen Petousis-Harris agreed.
"Halting during a clinical trial is not uncommon and pausing to investigate a possible safety signal shows that this vaccine is not being rushed and that safety is being carefully assessed... While this event could be vaccine-associated, it is more likely that it is not."
When New Zealand was at alert level 1 and without any known community transmission, there was talk of opening up the border with Australia and/or the Cook Islands. The outbreak across the ditch in Victoria put the trans-Tasman bubble on ice, and Auckland's outbreak a month ago ended hopes of an economic lifeline for the Cook Islands.
"A precondition for both was no community transmission, then our own cluster broke out, so you can see the Cook Islands would be a bit nervous about it," said Parker.
"The mechanisms are being put in place, but it really depends on both sides of the transaction not having any community transmission."
