Travellers from Auckland and Waikato are being granted exemptions to visit Covid-free areas of New Zealand without having to disclose if they have been vaccinated.
Leading expert in population health and epidemiology Professor Rod Jackson says this is a loophole that needs to be closed by the Ministry of Health immediately.
As of Friday, 3947 travellers had been granted exemptions by the Ministry of Health to cross alert level borders for personal reasons since the outbreak started.
Personal travel exemptions, such as the one sought and granted to a Covid-positive traveller to Hawke's Bay last week, are granted on a case-by-case basis "where this is consistent with the wider public health response", the ministry says.
The positive case was potentially infectious in Hawke's Bay before returning to Waikato and testing positive, but was asymptomatic and has been described as a "low risk" to the Hawke's Bay community.
The case's vaccination status has not been revealed by the Ministry of Health. It cites privacy reasons.
A ministry spokesman told Hawke's Bay Today the vaccination status of those who apply for an exemption to cross an alert level border for personal reasons is "not routinely collected" as part of the application process and was "not currently a requirement for granting an exemption".
Anyone granted an exemption is required to adhere to a range of public health advice, to minimise the risk of Covid-19 being spread outside the alert level 3 area, he said.
It was also not the norm for an exemption to be granted - the 3947 who had been granted was a small proportion of the 20,161 requests received exemptions.
Jackson, of the University of Auckland, said the fact that the ministry didn't require travellers to disclose their vaccination status before giving them an exemption was illogical.
"I understand the practicalities of this are not easy, but we just have to be staunch here.
"Anyone crossing the border right now should really be double-vaccinated and it's getting more and more pressing for this to happen.
"The [alert level] border has to be watertight, or at least Covid-tight, otherwise any loosening of restrictions means we would be looking at Covid ripping through the whole country."
Jackson said it was time for widespread vaccination mandates and this was one area the ministry should move on quickly, along with people like supermarket and hospitality workers and the police.
"Except in a community that is extremely highly vaccinated, Delta doesn't do amber and green - it's all red."
As of Saturday morning there were no positive cases in Hawke's Bay and just two known close contacts of the traveller, one who lives in Wairoa and one in Napier. Both have tested negative for the virus.
Latest tests of wastewater at sites in Napier, Hastings and Wairoa had also failed to detect any sign of the virus.
There is one location of interest in the region related to the traveller - Kmart Napier. They arrived in Hawke's Bay on Friday, October 15 and were at Kmart between 3.53pm and 5.13pm.
Those who were also there are asked to monitor for symptoms for 14 days.
If any develop, people are being told to get tested and stay at home until a negative test result is received and they have been symptom-free for 24 hours.
The Ministry of Health was on Friday urging the region to keep an eye out in case there are new locations of interest.
However, the spokesman told Hawke's Bay Today it was now "unlikely there will be any further locations of interest in the Hawke's Bay linked to the case".
Napier mayor Kirsten Wise said they had been informed by Hawke's Bay DHB that the case was a "low risk" to the region.
Kmart Napier said in a letter to staff that the case was a low risk to the store.
Anyone with any symptoms that could be Covid-19 – no matter how mild – are asked to call Healthline on 0800 611 116 for advice on getting a test.