The cots, ranging in price from $49 to $500, are from some of the country's most popular brands including Kmart, Target, Baby Bunting and Star Kidz.

CHOICE's annual safety testing revealed 18 of the 26 cots reviewed, failed key safety measures and could pose serious safety risks to babies.

"[This] is a really disappointing result," CHOICE testing expert Kim Gilmour said.

However, some manufacturers told ACM they disagree with the watchdog's testing methods.

Many of the safety failures were in relation to the mattress not being firm enough or not fitting snugly inside the portacot base.

"Soft or poorly fitting mattresses can increase the risk of sudden unexpected infant death," Ms Gilmour said.

"We also see problematic cot designs that have puffy covers that can also cause a risk."

Testing included whether cots have breathable zones on all four sides; sturdiness and stability; and the absence of hazards that could injury, entrapment or strangulation.

A Kmart Group spokeswoman said CHOICE's reviews were misleading and there had been no reported injuries relating to the mattress for Target and Kmart products.

"We disagree with CHOICE's claims concerning mattress firmness on the Kmart and Target portacots, particularly as both brands have tested this product to these same standards in an independent accredited laboratory and the results showed full compliance," she said.

"CHOICE do not use an accredited laboratory to test portacots. Our Kmart and Target portacots have been tested by an independent accredited laboratory and fully complied to the same mandatory and voluntary standards that CHOICE is referencing.

Baby Bunting also disagreed with the findings on its 4Baby Clouds 2 in 1 Portacot EA12117 and 4Baby Vacation Portacot EA12116. They provided CHOICE with results from an accredited lab indicating compliance to mandatory and voluntary standards.

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CHOICE said Star Kidz had provided test results showing its Vivo Super Light Travel Cot passed relevant safety standards.

Ms Gilmour said Australia's mandatory standards for portable cots are outdated, while some newer standards are voluntary.

"Newer standards were written for portable cots in 2010, [but] they haven't become law. Instead, they're used as voluntary standards that manufacturers are encouraged to adhere to - but they're not obliged to," she said.

CHOICE claimed the federal government had a reactive approach to product safety laws.

"Consumers have to wait until tragedy strikes for governments to take action and for businesses to take responsibility," Ms Gilmour said.