An exotic pest wasp that has made its way to the Cocos (Keeling) Islands could impact the lifestyle of those living on the islands and threaten Australian agricultural production.

The Macao paper wasp is believed to have arrived on the Cocos (Keeling) Islands, about 2,130 kilometres from mainland Australia, by hitchhiking on an asylum seeker boat.

Department of Primary Industries and Regional Development entomologist Marc Widmer has been working with the federal Department of Agriculture since 2016 in an attempt to eradicate the pest.

He said it was worrying how quickly pest wasp numbers had increased.

"We didn't really expect the explosion — and literally an explosion in the number of nests that we started to find," Mr Widmer said.

"One nest was found in 2015 and I went over to have a look at it and found a couple more, but by the end of that year we'd destroyed over 150 of them, so that's the capacity for them to spread."

Impact could be serious

While research into the Macao paper wasp was limited, and the exact impact on native flora and fauna was not certain, Mr Widmer believed the wasp would have an effect.

"They obviously build up in high numbers very quickly. They have very aggressive colony defence, and they have a really painful sting — and I can vouch for that myself," he said.

"They have large colonies — 600 wasps per family pizza-size nests — but they're usually quite well hidden so it's easy to stumble upon them accidentally, and that can [have] serious consequences if you can't run and get away quickly.

"They sometimes nest in houses. They're obviously going to affect local biodiversity through direct predation or competition for food and space, but we don't know what they're going to do to higher-order organisms."

The wasps are aggressive and have a 10 millimetre sting. ( Supplied: Marc Widmer/Department of Primary Industries and Regional Development )

Mr Widmer believed if the wasp was not controlled, it could have serious impacts on people living on the islands because of its size and aggressive nature.

"I got stung through my bee suit and thick jeans. They've actually got a sting that's almost 10 millimetres long, so they penetrated that clothing and even stung me through leather gloves," he said.

"Everyone in the islands, with that … perfect temperature, they wander around in bare feet and t-shirts and shorts, and they're not protected.

"If they were left, not being controlled and to their own devices, you'd find nests every hundred metres with hundreds of wasps."

The ABC has contacted local residents, who are currently not too concerned about the impact because the numbers have been reduced.

However, they hoped the wasp would be eradicated soon before anyone was injured.

Mr Widmer says if the wasp is not controlled, it could completely change island life. ( Supplied: Rik Soderlund )

Concerns for mainland agriculture

While the wasp has not yet made its way to mainland Australia, Mr Widmer said if it was to find its way here, it would be very concerning for the agricultural industry.

"They cause economic damage to grapes and figs, dates and peaches, and things like that in the Middle East," he said.

"And one of the main problems of course, they appear to be very good hitchhikers and we don't want them to find their way through shipping and other trade into mainland Australia."

Mr Widmer said the wasp was believed to have spread between the islands through "getting in hollow masts or just in nooks and crannies on boats".

"Some of the islands are 7km across the lagoon, and they found their way there — that's probably too far for the wasp to fly," he said.

"And considering we've seen wasp nests in boats that traverse between the islands, that's presumably how they're getting across to those islands … so I think that's a real risk to Australia."

Wasp would survive north of Sydney

Due to the warmer climate in the north of Australia, Mr Widmer believed the wasp might thrive in areas north of a line from Geraldton in Western Australia to Sydney in New South Wales.

"I can see no reason why they wouldn't thrive there. They'd have the food and the right climate, and the nest building materials," he said.

The Macao paper wasp is known to be a "good hitchhiker", and is believed to have arrived on an asylum seeker boat. ( Supplied: Marc Widmer/Department of Primary Industries and Regional Development )

However, in a statement to the ABC, the Federal Government's Department of Agriculture said it did not believe introduction to the Australian mainland was likely.

"The distance between [Cocos (Keeling) Islands] and the mainland is beyond the flight capacity of the wasp, as is the distance between most of the islands comprising the [Cocos (Keeling) Islands]," the statement read.

The statement said that under the Biosecurity Act 2015, all goods and vehicles were subject to biosecurity control going into Australia, and into external territories, including Cocos (Keeling) Islands, and were managed in the same way as international arrivals.

"This ensures that the risk of a pest or disease being moved between the island or being introduced to the mainland is managed appropriately."

Eradication still feasible

One year on from the beginning of the eradication process, Mr Widmer is confident the pest can be eradicated.

However, he is concerned that recent weather conditions may boost wasp numbers again.

"They've had 400 [millimetres] of rain, they've had a lot of rain [on the islands], and when it rains it can really rain," he said.

"I think that really retards the propagation, and it can even destroy nests, so they're hard to find in the rain.

"But when it clears and they start to get fine weather again, we expect we're going to find a lot of incipient nests, tiny little nests, starting again."