Quarantine officials are warning that inexperienced travellers are putting Western Australia's $8 billion agriculture industry at risk with tonnes of potentially destructive organic produce being seized at borders, and more detected every year.

Key points: Fresh fruit and vegetables are banned from being brought across the WA border, with some exceptions

Fresh fruit and vegetables are banned from being brought across the WA border, with some exceptions So far in 2019, about 1,600 kilograms of contraband produce has been seized from 9,000 vehicles in WA

So far in 2019, about 1,600 kilograms of contraband produce has been seized from 9,000 vehicles in WA As winter temperatures drive travellers further north, quarantine officers expect a spike in seizures

WA's Department of Primary Industries stopped almost 20 tonnes of contraband produce in 2018, some of which contained serious pests.

Quarantine officer Malcolm Harbor, responsible for ensuring anything that poses a bio-risk to the state is detected and destroyed, said the biggest culprits are novice travellers who seem ignorant of WA's strict biosecurity regulations.

"There's people who come into the state quite regularly and they seem to know quite a bit about quarantine in WA," he said.

"The green travellers who come into the state — they don't understand what restrictions are in place."

The Ord Valley is particularly susceptible to biohazards brought over the WA border. ( ABC Rural: Matt Brann )

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In 2018, officers seized about 17,500 kilograms of produce and 1,500kg of honey from 46,000 vehicles.

Potatoes and honey were the most commonly seized item.

Mango seed weevil and codling moths, serious pests with the potential to cause widespread destruction for WA producers, were detected at the Kununurra check point near the WA and Northern Territory border.

Mr Harbor said some travellers do not heed the warnings despite the risk of facing stiff fines and legal action.

"Compared to last year all the figures are up," Mr Harbor said.

Travellers are subjected to regular checks by quarantine staff at the WA border. ( ABC Kimberley: Sam Tomlin )

So far in 2019, about 1,600kg of produce has been seized from 9,000 vehicles.

Billion-dollar risk

It is a constant concern for quarantine officers who are trying to protect the state's $8 billion agricultural economy.

"Bringing these pests and diseases into WA will affect agriculture and eventually affect the WA economy," Mr Harbor said.

"WA's agriculture is fairly clean and green so that's why we want to make sure it is protected."

Quarantine inspector Michelle Bell searches the boot of a car on the WA-SA border. ( Supplied: Department of Agriculture and Food )

Fresh fruit and vegetables are banned from being brought across the border — even the boxes used to store the produce are not allowed because they could host diseases or insect pests.

However, the WA Department of Primary Industries and Regional Development lists a number of exceptions.

Beetroot, carrot, coconut, mushrooms, pineapple, sweet potato, and commercially packed leafy greens are some of the produce allowed.

Cooked and tinned fruit can be brought into WA but uncertified fresh fruit salad is not allowed.

With many travellers stocking up for long drives, Mr Harbor recommended cooking the produce before crossing the border.

"Anything that is cooked can come in to WA," he said.

"Do a shop that gets you to the border. Don't over shop — you can do a re-stock in town," he said.

As winter temperatures drive travellers further north, Mr Harbor's team will have their work cut-out in the coming months.