Thumbnails and videos of puppies and kittens are being edited into the clip of a gruesome suicide to trick social media users into clicking on the video.

James Sheahan Catholic High School principal Peter Meers sent a letter to parents and carers on Tuesday warning the school had been notified of the footage circulating across Facebook, Twitter, Instagram and Tik Tok.

The video is of a live suicide, which was likely to leave students "extremely distressed" if they watched it.

"We're also receiving reports that trolls are using videos of puppies and kittens to lure kids into seeing the video, and is being inserted into videos of kittens on Tik Tok," Mr Meers said in the letter.

"The clip is extremely graphic and has yet to be moderated. Should any this image appear in your feeds scroll past.

"We encourage parents to keep children offline today if possible, and heavily supervise all social media interactions until this content is removed."

In the letter, Mr Meers said the school had not alerted students to the video as teaching staff "do not wish to spike interest", but urged anyone affected to contact their child's year coordinator.

The letter included the phone numbers and website addresses for the Mental Health Line, the Kids Helpline and Headspace Orange.

Lifeline Central West CEO Stephanie Robinson said it could be incredibly distressing to young people and recommended children and teenagers avoid social media where possible.

"With such violent imagery and disturbing footage going around maybe today is not an iPad day and I know for me I'll be trying to distract my daughter with other things," she said.

"It's certainly not a day to let them go off with their own devices on their own.

"The thought of kids or someone seeing that makes me sick."

She said children who accidentally saw the video would need comfort and understanding.

"If they're of the age where you can have an honest discussion about it, be there for them and be open," Mrs Robinson said.