A child allegedly assaulted at a central Auckland park at the weekend is in a stable condition, police say.

The incident happened at Myers Park, near Queen St, about 4.45pm on Sunday.

Police said the child, who was taken to Starship Hospital with critical injuries, was doing well and remained in a stable condition on Tuesday. 

A 20-year-old man had been charged with attempted murder and was in custody.

The man was taken to hospital in serious condition following the attack as a result of self-inflicted injuries.

He was due to appear at the Auckland District Court this morning.

Police said the child and man did not know each other.