Elective surgery wait times have increased at Melbourne's Royal Children's Hospital, with some waiting more than a year for treatment.

Victoria's latest health performance data for the last quarter of 2022 showed the average wait time for non-urgent category three patients was 421 days.

That was up from 268 days, or an increase of 63 per cent, on the same quarter in 2021.

Category two, or semi-urgent patients, also waited an average of 126 days for surgery between October and December last year, compared to 84 days in the last quarter of 2021.

The surgery delays could have dire consequences for the state's children, the Victorian chair of the Royal Australasian College of Surgeons said.

"Coming out of the pandemic disaster, we have put resources into achieving timely care for the very urgent and acute cases," Dr Patrick Lo told 3AW Melbourne on Tuesday.

"But unfortunately, the category threes are still waiting.

"When you're talking about kids, they have got a very limited time to get that right otherwise they're suffering long term, well into adulthood."

The Royal Children's attributed the rise to increasing demand for services, higher acuity inpatients and the ongoing impacts of COVID-19.

"We understand waiting for any procedure can be a challenging time and we work closely with families to schedule procedures as soon as possible," a hospital spokeswoman said.

"We've recruited and are training more staff and in the coming weeks, this will allow the RCH to further increase activity as we open additional surgical theatre sessions."

Premier Daniel Andrews said the government was working with the hospital as part of its $1.5 billion COVID-19 catch-up plan.

"That's why every health service has more money. That's why every health service is at the table working with us to deal with that really significant surgical backlog," he told reporters in Melbourne.

"It's why we're seeing some positive early signs in terms of the total amount of surgery that we're doing and therefore ... clear signs that that waiting list is coming down."

He denied the waiting list was falling at a glacial pace as Victoria's total annual surgeries built towards 240,000 by 2024.

"That will serve us well not just dealing with the COVID backlog and that COVID catch up but it will mean the system is stronger," he said.

Opposition Leader John Pesutto called on the government to do more to address workforce shortages across the sector.

"We're hearing repeatedly across our health system that nurses and other allied health professionals are leaving the system in droves," he told reporters on Tuesday.

"The government needs to treat this system urgently."