A mum is warning other parents after her toddler was strangled by a onesie.

A mother has issued a warning to other parents, following a terrifying incident in which her three-year-old was strangled by her own onesie.

In a frantic Facebook post, Katie Price claims the suit, purchased from a UK department store, constricted her daughter’s airway, causing her to choke.

“She was so quiet in bed with me, I hear a weird noise and I turn around to her being choked by her onesie, the zip was too high on her neck and stopping her from breathing, she couldn’t even tell me or try get my attention because she was suffocating!” she wrote.

“Thank god I noticed. She is a little shook up right now of course, but she is fine!” [sic]

The UK woman urged other parents to take caution when putting their children to sleep in similar zip-up style pyjamas.

“I will never buy these again. I’d recommend any parent out there with these to do the same,” she wrote. “Who would have thought a simple onesie could almost kill a child?”

The 22-year-old's post has attracted over 24,000 shares and 10,000 comments in matter of days, including several questioning how such an incident could occur.

Price has since issued an update clarifying that her daughter had wriggled up in the bed, causing the suit to be pulled down at the back and the collar to tighten around her throat.

She claims the outfit was not too small and came with no warning about not being suitable for sleeping.

"This was also the first time I ever put her to bed in this," she added. "My house is freezing at night, I didn't once think that would happen."

Sleepwear safety.

KidSafe NSW advises that children sleep in nightwear that is appropriate for their size and weight and that the neck and armholes are closely fitted. This ensures minimal movement which could pose a potential choking/suffocation risk.

Tightly fitting sleepwear is also advisable for fire-safety reasons, as the looser the fabric, the greater chance of burns if it catches alight.