High-risk pests caught at New Zealand’s border

This section presents information on exotic mosquitoes and other insects caught at our border (international airports and seaports) by New Zealand’s mosquito surveillance programme.

It highlights which exotic mosquitoes are arriving at our border, where they are coming from, and how they are getting here.

There were 11 interceptions containing mosquitoes of overseas origin in 2019

Mosquitos of overseas origin include new exotic mosquito species entering New Zealand and exotic species established in New Zealand re-entering New Zealand from overseas.

In 2019, there were 11 interceptions containing mosquitoes of overseas origin. This compares to an average of 12 interceptions per annum between 2010 and 2019. Of the 11 interceptions in 2019, five contained mosquitoes whose species is already established in New Zealand. Six interceptions contained new exotic mosquitos.

Over 77% of all interceptions of overseas origin took place in the Auckland region between 2010 and 2019. Christchurch was the next most frequent location (11%) and then Wellington (7%). [1].

40 types of exotic mosquito species were intercepted, 2010–2019

Forty types of exotic mosquitoes were caught at the New Zealand border between 2010 and 2019. Nineteen were high-risk species, that is, on New Zealand’s list of exotic mosquitoes of public health concern [1, 2].

These included:

  • 22 interceptions of Aedes aegypti, a severe-risk species for many diseases eg, Chikungunya, Zika, dengue and yellow fevers.

  • 9 interceptions of Aedes vexans, capable of carrying West Nile virus.

Table 1 summarises all suspected mosquitoes of overseas origin caught at the New Zealand border, 2010–19 (See Table 1). 

Interceptions of overseas origin were most frequently from countries in the Pacific region

Of all interceptions of overseas origin, 39.5% originated from the Pacific region (Table 2). Between 2010 and 2019, Australia was the most common source country for interceptions (41 interceptions: 29 exotic mosquito, 12 non-mosquito, 2 unidentifiable. Note: two interceptions contained a mixture of exotic mosquito, non-mosquito or unidentifiable species). The next most common were Ecuador (14), USA (11) and Fiji (10).) [1]. 

Table 2: Number of mosquito and non-mosquito interceptions of overseas origin, by region and country,

Region of Origin Country of origin (Number of interceptions Percentage of Total Interceptions Travel  mode



Australia (41), Fiji (10), Tonga (3),
New Caledonia (2), Samoa (2), Niue (1),
Papua New Guinea (1), Tahiti (1), Vanuatu (1)
Total: 62


Sea: 72.6%
Air: 27.4%


India (7), China (6), Japan (4), Singapore (4),
Philippines (3), Thailand (3), Hong Kong (2),
South Korea (2), Malaysia (2), Taiwan (2),
Bangladesh (1), Cambodia (1), Indonesia (1),
Vietnam (1)
Total: 39


Sea: 64.1%
Air: 30.8%
Unknown: 5.1%


Ecuador (14), USA (11), Chile (2), Colombia (2),
Argentina (1), Mexico (1), Panama (1)
Total: 32


Sea: 84.4%
Air: 15.6%


Germany (3), UK (2), Belgium (1),
Netherlands (1)
Total: 7


Sea: 100%


Unknown (17)
Total: 17


Sea: 17.6%
Air: 76.5%
Unknown: 5.9%

Data source: New Zealand BioSecure, 2020.

High-risk pests most often travel by sea and in ‘other cargo’

Between 2010 and 2019, 68.1% of mosquito and non-mosquito interceptions were suspected to have travelled by sea [1]. In 2019, over 99% of imported goods to New Zealand were transported by sea [3].

Between 2010 and 2019, 35.2% of interceptions of suspected mosquitoes of overseas origin were found transported alongside other cargo (eg, household goods, shipping containers—contents not specified). Fruit (eg, bananas, grapes) made up 18.0% of discovery locations at the New Zealand border, followed by 11.5% each for the transit zone, tyres, other produce, and baggage (Figure 1).

Figure 1:Mosquito interceptions of overseas origin, by location of discovery at the New Zealand border, 2010–2019 (%)


1. New Zealand BioSecure Entomology Laboratory. Mosquito interceptions dataset. Southern Monitoring Services Limited. (Accessed 2020 by personal correspondence)

2. New Zealand BioSecure Entomology Laboratory. Exotic Mosquitoes. Southern Monitoring Services Limited. (accessed May 2020). Available at: www.smsl.co.nz

3. Statistics New Zealand (Statistics NZ). Infoshare. Overseas cargo statistics: Total imports by New Zealand port
(Annual-Jun). URL: www.stats.govt.nz (accessed May 2020).

Downloads Back to Top