A single male was discovered in a Ministry for Primary Industries trap in Grey Lynn on Monday - igniting fears across the horticulture sector and a major biosecurity response, including tight restrictions on fruit and vegetable movements in parts of Auckland.
More traps have been set and officials must now wait and see whether any more are found. This is the fourth time the fly has been found in northern New Zealand since 2012.
So why is this fly so bad?
The answer is simple. Adults lay eggs in ripe fruit, maggots hatch and tunnel through the fruit flesh and turn it into pulp. This means no one can eat the fruit - and on a large scale can mean massive losses for farmers.
Given this, New Zealand's $5 billion horticulture industry, including the Bay's kiwifruit sector, has every right to be worried.
As reported in Thursday's Bay of Plenty Times, Kiwifruit Vine Health says it is "unacceptable" that fruit flies are being found here.
A report by the organisation last March says the worst-case scenario would be if a breeding population was found in Te Puke. It would cost $430 million a year and trigger "severe market reactions".
This week's discovery has again led to questions over the country's biosecurity measures.
Labour and the Greens claim frontline staff cuts are to blame and that our biosecurity measures are "flimsy".
At first glance, it is easy to write off these criticisms as politics. Of course, opposition parties are going to criticise the Government every time something goes wrong.
But this has been a thorny issue for some years and the critics have a point.
Back in May 2012, Te Puke kiwifruit grower and Horticulture New Zealand president at the time Andrew Fenton wrote that in 1996 successive fruit fly discoveries prompted the introduction of biosecurity x-rays for passenger bags and in the next 16 years no more were found. In 2011, the Government stopped x-raying all baggage and in May 2012 a fruit fly was found. It's hard to believe this is a coincidence.
Currently, the bags of New Zealand and Australian citizens are not x-rayed although passengers must fill out declarations and sniffer dogs are used.
Critics say this is not good enough and this week called for all baggage to be x-rayed again and the Greens want a ban on fruit and vegetable imports from Australia until stronger measures are in place.
Kiwifruit Vine Health wants all luggage from Australia x-rayed in the high-risk season between January and April, and higher levels of screening for fresh produce.
The Government rejects these criticisms, repeatedly saying biosecurity is a top priority and last July pointed out that 125 new quarantine inspectors had been trained in the previous 18 months and 12 new x-ray machines installed at international airports.
The ministry says it has all the resources it needs, has lots of equipment and additional dogs.
Prime Minister John Key points out fruit flies are prolific in Australia but that authorities here are doing all they can to stop pests crossing the border.
So, who's right?
I agree with growers. Four cases since 2012 is too many. There must be no shortcuts when it comes to protecting our border.
The fly can only get here four ways: by cargo, ship, mail or passenger. Obviously it is unknown how this latest one arrived but given that 10 million passengers cross our border each year and 175,000 items each day, tougher measures are urgently needed.
The jury is out on whether this latest find is an isolated case but it only takes one dishonest person with infected fruit to slip through the net to cause financial ruin.
If biosecurity really is a top priority, then all baggage must be x-rayed again.
I cannot understand why we wouldn't do this.
Sure, it might inconvenience some passengers and cost money but these costs are nothing compared with what will happen if these pests ever established themselves here.
The Government needs to convince the public that all possible measures are being taken.
The risk is not worth it.
