The South Island has its first Covid case in 12 months - a person who flew from Rotorua to Marlborough and who has been linked to a Waikato cluster.
The Ministry of Health has confirmed the case is now isolating in Blenheim.
"It comes after the individual late last night returned a positive Covid-19 test result," the ministry said in a statement.
"The individual flew from Rotorua and arrived in Blenheim on [Thursday]. The individual sought a test upon arrival after developing a sore throat. The initial test, including a follow-up swab, returned a weak positive result.
"Investigations into the source of the infection are underway. However, initial case interviews suggest the case is linked to the Te Awamutu cluster."
The ministry said the current public health assessment was that the risk appeared low given the individual's likely late stage of infection.
"So far, initial case interviews have identified a small number of close contacts, who have been contacted and are currently isolating with tests arranged.
"Interviews are also being undertaken to determine any locations of interest."
News of Delta finally hitting the Mainland after a year dodging the virus has hit Blenheim businesses hard.
Annette Gould, manager of Copper Beech House, was left shaken by the news.
"It doesn't surprise me, I guess we've been waiting for this to happen but I've really got to get tighter in the hostel," said Gould.
She is now considering mandatory vaccination proof for all visitors.
"I might say no newcomers unless they are vaccinated, and those already here, they have until the end of November to get vaccinated, I don't know," she said.
"If we get one hit on Covid, we have to shut down and everyone will lose their job. The repercussions will be huge."
The popular hostel, which has had some international visitors staying for nearly two years because of the global pandemic, has enforced QR code scanning throughout the Covid-free months.
Regular updates are posted on a board, and around 80 per cent of visitors have been vaccinated.
The hostel caters for up to 60 guests, with visitors all working locally, in vineyards, wineries, factories, construction and hospitality.
A widespread outbreak would be devastating, Gould says, and she encourages all backpackers to get the jab.
"We've survived it this far, with two lockdowns, and the first one was hell, the second one scary, and we've managed to keep going," she said.
"Every day you touch wood and hope everyone is being sensible."
One Blenheim business manager said they had systems in place if alert levels changed.
"For most of us, it'll just be a case of 'Here we go again...'."
The shock case was the "kick up the backside" the South Island needed, according to Pete Coldwell, general manager of the Marlborough Chamber of Commerce.
He said South Islanders had felt "isolated" from the virus and lived a relatively normal life over the past 12 months, so he hoped the new case would prompt the unvaccinated to get the jab.
Hospitality and tourism have been hardest hit by Covid-19 in the Marlborough region, but many other businesses have suffered knock-on effects.
However most businesses were returning to "some semblance of normality" until today's news.
"Today they're just wondering if they'll be locked down again," Coldwell said.
"Hopefully, this latest case is truly isolated and it doesn't spread. And if that scenario comes through then it's just a case of vaccinate, vaccinate, vaccinate...
"It's going to get here again – at some point – even if they do contain this one. So we just need to get the vaccination numbers up and get them up quickly."
People in Blenheim were being urged to check the regularly updated locations of interest list.
"We are also asking Blenheim residents with symptoms – no matter how mild – to please get tested, even if they are vaccinated."
Testing in Blenheim is available at:
• Blenheim CBAC: Horton Park, off Redwood St, 9am-5.30pm on Saturday, Sunday and Monday
• Nelson CBAC: Saxton Field parking area, Suffolk Rd, Stoke, 10am-6pm on Saturday, Sunday and Monday
"Additional testing capacity in the area will be stood up, if needed, and details will be available on the Healthpoint website," said the Ministry of Health.
"Meanwhile, those in Marlborough, Nelson and Tasman are reminded to get vaccinated this weekend if they have not already. Vaccination clinic locations across the region are available on the Nelson Marlborough Health website.
"So far, vaccination rates in the Marlborough region have remained steady with 90 per cent of residents having received their first dose, and 78 per cent fully immunised.
"The ministry is monitoring the situation and will provide further public health advice if, and when, required."
Marlborough Mayor John Leggett said he understood the person who tested positive was isolating.
He was not sure how widely the person had travelled in Blenheim and said contact tracing was underway.
However, the high rate of vaccination in the district was reassuring.
The mayor added that the council will be supporting health professionals called in to deal with the case.
Before today, the South Island has had no Covid cases in the community since November last year when two health workers caught the virus while working in a managed isolation and quarantine (MIQ) hotel.
As of Friday morning, the West Coast DHB had the South Island's lowest fully vaccinated rate of 62 per cent, with Canterbury second lowest at 64 per cent, according to Government data.
Further ahead are the South Canterbury DHB with 69 per cent fully vaccinated, and Southern and Nelson Marlborough both with 72 per cent.
Blenheim has been at the centre of several cases involving Aucklanders allegedly travelling in breach of Covid travel restrictions.
A businesswoman who flew from Auckland to the Marlborough Sounds for a property appraisal was charged three weeks ago for breaching Covid-19 restrictions.
Police have summonsed the 53-year-old woman to the Blenheim District Court on October 26, and health authorities were notified.
A spokesperson said police were tipped off last Tuesday and spoke to the woman on Wednesday.
The Herald understands she is an early childhood education business owner and had travelled to Marlborough to have her holiday home appraised.
Her work and social media pages list Wellington as her home city.
However, the Herald understands she was living in a central Auckland flat during alert level 4 and 3 this year, and police had visited the apartment last week as part of the inquiry.
And last week, two women who sparked a Covid-19 scare in the South Island were ordered to return to Auckland.
The pair appeared in Blenheim District Court on Thursday afternoon last week.
The duo appeared via video link from Blenheim police station, facing charges of failing to comply with an order made under section 11 of the Covid 19 Public Health Response Act 2020.
They were bailed with no plea back to Auckland and ordered to reappear in court later this month.