Three more live spiders have been discovered in imported Mexican grapes but no bites from venomous species have been reported so far.
The Ministry for Primary Industries (MPI) has been working with supermarket chains to remove all Mexican grapes from shelves after the first poisonous spider was discovered on Friday last week.
The ministry earlier this week said 10 spiders had been discovered, eight of which were thought to be poisonous.
Since then, three more live spiders have been discovered, bringing the total to 13.
However, identification of the spiders had found only seven were poisonous - three black widows and four yellow sac spiders.
The remaining six spiders were identified as spiders from different families "that present no human health risk".
MPI spokesman Jim Flack said there had been no reports of anyone being bitten by a grape spider.
The ministry's pests and diseases hotline had received about 50 calls as of yesterday concerning spiders in Mexican grapes.
"Not all of these callers were reporting actual spider finds. Many were people seeking general information."
Mr Flack said the National Poisons Centre had advised that anti-venom was generally not required for black widow spider bites, but if anti-venom was required, then redback anti-venom should be used.
"Most major hospitals in New Zealand stock this anti-venom."