Welsh ambulance service chiefs have urged the public to “drink sensibly” at new year to help reduce demand on emergency services that suffered a 340-call backlog on Monday.

Jason Killens, chief executive of Welsh Ambulance Service, made the plea after the service declared a critical incident.

In addition, more than half of the trust’s ambulance vehicles were waiting to hand over patients outside hospitals.

Mr Killens asked the public to use the service “wisely” and only call during a “genuine emergency”, and said it was prepared for the additional pressure and 999 calls.

Speaking to BBC Breakfast, Mr Killens said there were delays at urgent and emergency care departments which prevented ambulance staff handing over patients.

He said that one of the reasons for the pressure on the health system was down to winter viruses such as flu and Covid along with other factors.

“The pressure across the urgent and emergency care in the NHS is well documented. It’s a challenge here in Wales as it is in the rest of the UK,” he said.

Mr Killens said other factors had also contributed to the pressures placed on the system.

“It’s caused by many factors some associated with patients that are medically fit for discharge being unable to get back in to the communities because of the pressure in adult social care,” he said.

However, he added that while the pressure had continued overnight, the number of ambulances waiting was slightly less.

“As we go through this morning and we see the numbers of calls coming into us rising throughout the day as we normally would, we will see that similar situation of pressure arise today,” he said.

He apologised to patients waiting “far too long” but said there were plans in place to manage the backlog of calls.

“We do have doctors, nurses and paramedics providing advice over the phone and managing less serious patients in a different way so we can respond to those much more sick patients as quickly as we can,” he said.

Mr Killens also thanked the staff and volunteers for their work during the critical incident.

On Monday, the Welsh Ambulance Service described the situation as “very rare”.

Speaking to BBC Radio Wales Breakfast, Mr Killens explained that declaring a critical incident “signals the the rest of the NHS that we’ve got a problem, we are under extreme pressure and we need help”.

South Wales Fire and Rescue Service said it would support the ambulance service, urging people to call 999 “for serious emergencies and where life is at risk”.

“With the pressure on the NHS and the yellow weather warning for Wales over the coming days, we expect demand for emergency services to be high,” said Christian Hadfield, assistant chief fire officer.

Health boards in Wales have reiterated the ambulance service’s message only to call 999 or go to hospital with life-threatening symptoms or in an emergency.

A spokesperson for Cwm Taf Morgannwg University Health Board said its hospitals were extremely busy.

They said: “None of us wants to start 2025 in a busy emergency department or in the back of an ambulance so please take care as you celebrate the new year and think carefully about whether your health need is an emergency.”

A spokesperson for Hywel Dda University Health Board said its hospital sites, especially emergency departments, were under “extreme pressure”.

A spokesperson for Cardiff and Vale University Health Board said it was experiencing operational pressures following the Christmas break.

“The increase in flu both in the community and across our hospital sites has resulted in several ward closures with 100 beds currently closed of which 10 are empty – we expect this to increase over the next few days,” they said.

A spokesman for Aneurin Bevan University Health Board said its services were facing the same extreme pressures being reported across Wales and the UK.

“We are currently operating at a level 4 escalation status, with the demands prevalent across our entire system and unfortunately causing long waits for our services and impacting the flow of patients through our hospitals.”

Dr Rowena Christmas, chair of the Royal College of GPs in Wales, said the situation was worrying and had been for several years.

She said: “The amount of acute respiratory illnesses we are seeing at the moment is extraordinary.”

Marie Curie Cymru’s Jon Antoniazzi called the critical incident “deeply troubling.”

“While winter pressures are a constant challenge, on behalf of all people with a terminal illness and their families in Wales, we must draw a line under this and say enough is enough,” he said.

A critical incident was also declared in December 2020, due to high demand, particularly in south east Wales.

But an extraordinary incident was declared in 2023 after an ambulance spent more than 28 hours outside a hospital.

The Welsh government said urgent and emergency care services across Wales continued to see high levels of demand this winter.

A spokesperson said: “We are urging people to only call 999 in the event of a life-threatening emergency and to carefully consider where to go for care. For urgent care needs, NHS 111 Wales can be accessed 24/7 online or telephone service for advice and signposting.

“Increase in flu cases has further added pressure during the Christmas period and resulted in action being taken by health boards including prevention and control measures.”