A surge of admissions at Princess Margaret Hospital last weekend caused cases of non-elective surgery to be delayed more than 24 hours.
Eleven-year-old Harry Ginn, who needed surgery on a badly infected cut on his hand from falling off a bike on Boxing Day, was told last Friday night he would have to come back for surgery the next morning.
After what a PMH spokesman described as "an exceptional number" of non-elective surgery cases presented to the hospital on Saturday, Harry's surgery had to be delayed until 11am on Sunday.
The delays were compounded by the complexity of some of the cases, the spokesman said.
Harry's mother Nardia said nurses apologised for the delay and surgeons were available to operate but only one theatre was open.
"Other children a lot younger were very distressed because they had been fasting the same amount of time as Harry," she said. "A child had stayed there for two days with a dog bite before he could be operated on."
Shadow health minister Roger Cook asked if the State Government had given PMH enough resources.
The PMH spokesman said it was standard practice for one theatre to be open on weekends, with more opened for urgent cases or multiple trauma.
"In this case, senior clinical staff were satisfied that the clinical outcomes of all deferred cases would not be affected," the spokesman said.