"But you can easily recognise the web, which is quite messy and untidy.
"They like to hang out at the edge of pot plants, or anywhere under shelter, like under seats. They are usually very small."
Mr Brunel said when he was first contacted by the Rotorua property owner he was sceptical, "but when I'd seen the evidence I was totally sure".
"There have been white tail spiders here for 100 years, they are not a big deal, but these things are.
"We may not find another one, but it was a female so she may have had a few more.
"It begs the question how it got here in the first place.
"They [property owners] didn't bring it in from Aussie, because they haven't been there lately."
Mr Brunel said the public should be aware of the dangers around redback spiders.
"If a kid got bitten I don't know what sort of time they may have."
An MPI spokesperson confirmed photographs of the spider found in the Glenholme garden were sent to its Christchurch laboratory and it was identified as a redback.
"They have been established in parts of New Zealand since the 1980s.
"They have been found in Central Otago, Taranaki and occasionally in other areas of New Zealand," the spokesperson said.
The redback spider (Latrodectus hasseltii) is a species of venomous spider indigenous to Australia.
The adult female - the dangerous one - is easily recognised by her spherical black body with a prominent red stripe on the upper side of her abdomen and an hourglass-shaped red or orange streak on the underside.
Females have a body length of about 1cm, while the male is much smaller, being only 3 to 4mm long.
An effective anti-venom was developed in 1956.
According to the Ministry of Health, redbacks will only bite when disturbed or trapped in clothing, and bites are rare.
If people believe they have found redbacks, they can call MPI's pests and diseases hotline on (0800) 80 99 66 .