BioSecurity Queensland has reportedly spent more than $3.2 million on the National Red Imported Fire Ant Eradication Program since the insects were discovered at Fisherman’s Landing six months ago, with helicopters used for surveillance operations.

Program director Mike Ashton told the ABC the ants might have been shipped into Gladstone with construction cargo.

"We believe they've come from the southern United States," he reportedly said.

"We've done genetic analysis of the fire ants in Yarwun and we believe we can trace them back to somewhere ... in the southern US. [They were] probably in some equipment that's been brought in as part of the construction of the LNG plants."

The Curtis Island LNG plant-building boom has also been linked to a spike in sea turtle, fish and dugong deaths over recent years.