Queensland’s chief health officer Dr Jeannette Young said strawberry eaters in Queensland, New South Wales, Victoria and the Australian Capital Territory should cut the fruit in half before eating, no matter the brand.

Police are investigating a copycat saboteur after a Coles employee at a Gatton store, about 90 kilometres west of Brisbane, found a "small silver rod" on top of strawberries in a punnet.

The incident was reported to authorities on Thursday, but the strawberry punnet targeted was not a Berry Licious or Berry Obsession brand, leading to Dr Young expanding the health warning.

Acting Detective Chief Superintendent Terry Lawrence re-emphasised his warning to anyone who found a metal object in their strawberries to report to it police so it could be collected as evidence.

"This morning an employee of that particular [Coles] store bought a punnet of strawberries and located within that packet a small silver rod. It was lying on top of the strawberries, not inserted per se," he said.

"They brought that to the attention of the shop manager who, in turn, immediately brought it to the attention of the Queensland Police Service."

The Berry Licious and Berry Obsession brands have been removed from shelves across Queensland, New South Wales, Victoria and the Australian Capital Territory.

"We're comfortable that all the products related to Berry Licious and Berry Obsession from those particular dates, that's been resolved in the sense that those products are no longer being sold and they've been taken off the markets," Acting Detective Chief Superintendent Lawrence said.

"However, with the copycat occurring at Gatton, it's very important for us to put out that message that we want everybody to check their strawberries before consuming them."

Dr Young said her advice remained that anyone with Berry Licious or Berry Obsession strawberries should throw them away or at the very least cut them in half to check for any dangerous objects.

"Given this new information from police, I have had to modify my advice to people," she said.

"So, yesterday I said anyone who had bought those products since the start of last week needed to dispose of them.

"I now say, given there has been these additional incidents unrelated to that particular product, my advice is just to be ultra-cautious and simply cut up those strawberries before consuming them."

On Wednesday, a woman in Gladstone, on the central Queensland coast, narrowly avoided feeding contaminated strawberries to her son, posting photos of the fruit online.

Angela Stevenson warned friends that she had cut open a punnet of Berry Obsession strawberries when she found two needles embedded in the fruit.

"I can confirm a fourth incident, that incident took place at Gladstone, within the last few days," acting Detective Chief Superintendent Lawrence said.

"A young 10-year-old child was at school, consumed or began to consume a strawberry and found a needle within and reported that to the school.

"The school spoke to the child's mother who did an examination of the punnet of strawberries she had at home and found another needle within a strawberry in that lot there."

It was the fourth contamination incident to be reported across Victoria and Queensland.

The separate copycat incident takes the number of strawberry punnets in Queensland and Victoria found to contain dangerous metal objects inside, to five.

Queensland man Joshua Gane reported the first contamination on Sunday when his friend swallowed "half a sewing needle" after biting into a strawberry.

Two more cases were reported in Victoria on Tuesday night and confirmed the following morning, after contaminated punnets were found in Woolworths stores in Yarram and Ballarat.

The Gladstone case and copycat saboteur were revealed on Thursday after the two contaminated brands were removed from shelves on Wednesday, following the initial health warning.

Queensland Strawberry Growers Association industry development officer Jennifer Rowling claimed on Wednesday night that a "disgruntled ex-employee" could be responsible for the contamination.

However, Chief Superintendent Lawrence said the police investigation was ongoing and detectives were examining every part of the supply chain to find the contamination source.

"The idea of an ex-employee was put forward by the Strawberry Growers Association. We're not agreeing with that at all at this particular point in time; our investigation is still open," he said.

"We're not going to go into speculation. We're keeping a very open mind as to where this may have occurred."

Chief Superintendent Lawrence said those responsible for contaminating the fruit could be charged with maliciously causing grievous bodily harm, an offence which carries up to 10 years' imprisonment if convicted.

On Thursday, officers returned to the two contaminated farms, situated next to each other in south-east Queensland, belonging to the supplier behind the Berry Licious and Berry Obsession brands.

Police were gathering a full list of current and former farm employees and speaking to them all.