"This is a disgraceful dereliction of duty. It puts the whole economy at risk, the natural biodiversity, the marine biology supporting aquaculture as well as the horticulture and agricultural industries."
Mr O'Connor said it was also "disturbing" that Mr Carter "sat on these figures for more than a week" during the recent Queensland fruit fly quarantine in Auckland.
But Mr Carter defended the reduction in biosecurity staff numbers, saying most of that was associated with the reduction in imports because of the global financial crisis.
The cost of biosecurity was recovered from importers.
"It was only fair then to drop staff numbers, otherwise the cost to importers would proportionately increase."
Further vacancies were not filled when the ministries of agriculture, fisheries, food safety and biosecurity were merged.
The new Ministry of Primary Industries was now stabilised, "and they are now advertising this weekend for a further 40 airport biosecurity staff".
Mr Carter said New Zealand's biosecurity defences were now stronger than ever despite fewer staff.
"We're far better targeted and better at profiling passengers and goods than we were in 2008".