But police are yet to identify a strong lead as they investigate the strawberry industry's itinerant workforce.

"How could any right-minded person want to put a baby or a child or anybody's health at risk by doing such a dreadful act?" Ms Palaszczuk told reporters on Saturday.

The reward has been offered amid fears six brands across four states have been targeted with needle insertion.

Fruit sold under Berry Obsession, Berry Licious and Donnybrook brands originating from Queensland have been withdrawn from retailers.

NSW police have warned that fruit sold under the Love Berry, Delightful Strawberries and Oasis brands had needles inserted by a possible copycat.

"This is putting families' lives at risk and it's also putting the strawberry industry at risk," Ms Palaszczuk said.

"We need to catch those responsible."

A fresh report of a contamination in Townsville is being investigated, Queensland police said, following instances elsewhere in the state, as well as Victoria and NSW.

The hunt for the culprit is not limited to disgruntled employees.

"Our investigation is ongoing. It's fairly complex and fairly large because of the itinerant nature of employees in the industry," Detective Superintendent Terry Lawrence said.

"I won't go as far as saying we have specific leads.

"If we can narrow it down to a smaller geographical location and particular farms, that would be great for us."

Products sold under the labels have been pulled from shelves but it is unclear just how big the health issue has become with punnets being sold across Australia.

A health warning to throw out or cut up strawberries remains in Queensland, NSW, Victoria and South Australia.

But authorities have stopped short of discouraging consumers buying strawberries.

On Thursday, Queensland police announced they were also investigating a suspected copycat incident after a metal rod was discovered on top of strawberries inside a plastic punnet at Coles in Gatton.

Australian Associated Press