Twelve patients have become the first to be admitted to a temporary field hospital at the Principality Stadium in Cardiff.

Ysbyty Calon Y Ddraig, the Dragon’s Heart Hospital, is the largest temporary hospital in Wales and the second largest in the UK, providing up to 2,000 additional beds for Covid-19 patients.

On Wednesday, Cardiff and Vale University Health Board said the site had now welcomed its first patients nine days after it was officially opened by the Prince of Wales on April 20, with more expected later in the week.

They will be transferred to the stadium – home to the Welsh rugby union men’s team – from University Hospital of Wales in Cardiff and University Hospital Llandough in Penarth as they continue their recovery from coronavirus.

Stuart Walker, executive medical director at the health board, said a number of beds were being opened up to prepare for a potential increase in demand when social distancing measures are relaxed.

He said: “Those increases may materialise to some degree over the next few weeks, and it was always our intention to use some beds at Ysbtyty Calon Y Ddraig, as soon as appropriate to do so, as part of our normal UHB bed base – alongside our core hospitals plus Barry and St David’s Community Hospitals.

“We may also need to offer some surge capacity to neighbouring regions, plus to offer some capacity to local residents of Care and Nursing homes to facilitate separation of residents with and without Covid infection.”

The first patients have move into a 25 bedded ward, staffed by a ward sister, registered nurses and eight health care support workers.

Nearly 400 staff have undertaken induction training and will be brought on site as more patients are admitted.

The hospital has double the size of Cardiff and Vale University Health Board’s system, with patients being treated in large tent-like structures and stadium hospitality boxes.

Around 750 beds are on the pitch, with 250 on platforms around it, and there is on-site radiography, laboratories and a pharmacy.

The tented structure housing wards on the stadium’s pitch is around eight times the size of Glastonbury festival’s main stage, while enough temporary energy is being fed into the hospital to power a small town.

Planners expect around 1,000 clinicians and 600 support staff to operate the facility on a single shift.

It will care for patients who are coming to the end of their treatment for Covid-19 and require rehabilitation and support, or end-of-life palliative care.

Facilities include mobile x-ray, CT scanners and care for people in the last weeks or days of their lives.