It will take “a number of years” for NHS waiting times in Wales to recover to pre-coronavirus levels, the organisation’s boss has warned.
The number of people waiting more than nine months for planned hospital treatments is at least five times higher than at the start of 2020.
Waiting list figures will be published later, for the first time since March.
This was when most non-urgent treatment was postponed to prepare the NHS for the first coronavirus wave.
Since then, the service has been trying to restart non-emergency treatments and aims to keep them going as much as possible during the second wave.
Despite recent progress, NHS Wales chief executive Andrew Goodall warned waiting times could grow even further – saying is “real concern” was hospital doctors only being able to see about half as many in-patients and day cases as normal.
He believes there will be a third fewer out-patients seen and operating theatres working at half their usual capacity due to infection control measures.
Data showed that between March and August there had been a five-fold increase in the longest waiting times of more than 36 weeks.
“The overall waiting list has not changed so much, it’s simply patients have been shifted more to the end of the list as we’ve had to prioritise urgent and emergency cases,” Mr Goodall added.
“We have made a lot of improvement on waiting times in recent years and it will take us a number of years to recover that and it will take investment and resources also.”
The last figures published in March related to waiting times in January.
They showed 462,358 patients were waiting for hospital treatment, of those 49,548 (10.7%) had been waiting between 26 and 36 weeks and 27,314 (5.9%) had been waiting longer than six months.
The longest waits included 8,721 people waiting for orthopaedic or trauma treatment and 47 waiting for cardiothoracic surgery.
The figures also showed the average (median) time patients had to wait for hospital treatment was 10.8 weeks, the longest since September 2017.
Welsh Government targets state 95% of patients should be treated within six months and nobody should wait longer than six months.
Recent analysis by the BBC Wales Investigates programme suggested at least 49,000 people in Wales were waiting more than a year in September and for six out of seven health boards, at least 25,000 were waiting for surgery.
That would amount to a tenfold increase in the number of patients compared to September 2019.
The Welsh Government said “difficult decisions” were made to postpone surgery and outcomes for patients would have been even worse had it not acted.
The NHS has gradually resumed non-urgent activity since the first wave and is trying to get procedures done, in so far as that is possible, but it has been substantially lower than what is usual.
Along with waiting times figures, the Welsh Government will publish for the first time three new “experimental” performance measures for A&E departments:
No targets have been set in relation to these measures and the Welsh Government said they were set with input from frontline emergency care staff.
Jo Mower, vice-president of the Royal College of Emergency Medicine in Wales, has been a consultant in Cardiff for the past 16 years.
She said she was confident the new measures, alongside the current time-targets, would be better for those who came to A&E themselves, as well as those who arrive by ambulance.
“There may be times when we’re overwhelmed, but we want to ensure our patients are triaged and assessed as close to their arrival time as possible, so the patient can get the right treatment, especially for those critical interventions like heart attacks, sepsis, strokes – and this will identify those patients but also those who could possibly wait a little longer for their treatment.”
The current target is 95% of patients should spend no longer than four hours in A&E, but this has never been met since it was introduced in 2010.
The last published figures showed that in February, 79% of patients spent less than four hours in urgent care departments.
More than 4,000 patients spent more than 12 hours in those departments, even though the targets state nobody should have to wait that long.
However, critics of the current measures say they give little indication of the quality and urgency of care given to patients.
Dr Goodall said once the pandemic has been brought under control, the NHS would need to transform the way it works in order to tackle the backlog.
But he said the rapid changes made to deal with Covid-19 – such as the growth in video consultations – proved what was possible, and he believed ministers would consider long-term funding challenges.
“I personally feel our longest waiting times may still take a number of years to resolve. But what I don’t want to happen is we continue to respond in the same old fashioned way.”