WITNESSES have described how they tried to shield their young children from the aftermath of a stabbing at a popular riverside playground as a father lay bleeding from wounds allegedly inflicted by his former wife.

Mother-of-two Michelle Allison Fernandez is accused of stabbing Mark Fernandez with a 20cm kitchen knife after he handed over one of their children at the busy Shelley foreshore in October 2015.

The alleged attack left Mr Fernandez with his intestines hanging out of his body and severe cuts to the nerves and tendons in his hand.

Ms Fernandez is on trial in the District Court after pleading not guilty to causing grievous bodily harm.

She says her former husband brought the weapon to the park and her actions were in self-defence.

Testifying yesterday, primary school teacher Kylie Stone, who was at the park on the morning of the incident with her two young children, said she watched Mr Fernandez playing energetically with his child for about an hour.

Ms Stone said soon after Mr Fernandez left the playground with the child and three other adults, she heard him yelling “help me, help me”.

She said her initial thoughts were that it was a joke, but when his calls for help became frantic, she looked up to see Mr Fernandez on the ground with Mrs Fernandez on top of him.

In a triple-0 call played to the jury, Ms Stone was heard saying “we’re not sure who stabbed who, but there’s a lot of blood”.

Speaking with a police officer in another call several minutes later, Ms Stone said there were “adults and kids everywhere” and Mr Fernandez was in a “bad way”.

"The mother involved said he came at her with a knife and there was a tussle," she said.

"He's in a bad way, he's been stabbed in the stomach and I think it is the knife that she tried to get off him."

Another witness, Claire Watkinson, told the court she heard a female screaming which prompted her to collect her children from the playground.

“It was a very guttural, scary scream,” she said.

“Almost every mother at that park reacted in the same way and began calling for their kids.”

Ms Watkinson said after a bystander threw the bloodied knife away from the melee, she wrapped it up with a plastic shopping bag because she did not want the children to see it.

She said she walked Ms Fernandez, whose hands were covered in blood, to a nearby park bench to calm her down.

Ms Watkinson said she asked Ms Fernandez what had happened, to which she replied “you wouldn’t understand, he’s been following me”.

Other witnesses described hearing a child say “I don’t want mummy to go to jail” during the ordeal.

The court was earlier told Mr Fernandez was upset that one of his daughters did not want to see him and the handover at the park tipped him over the edge.

He needed 105 stitches in his upper body and 138 stitches in his hands.

The trial continues.