The Emergency Department (ED) at the Queen Alexandra Hospital in Portsmouth will be getting a multimillion pound makeover.
Final plans have been approved with £58 million of national funding in place.
Building work has started with a planned opening date of Winter 2024.
The changes will see the Portsmouth Hospitals University NHS Trust double their current resus capacity from four adult bays to eight for patients needing treatment for critical conditions.
There will also be two further paediatric resus bays for children and increased privacy and dignity for patients with treatment in single bay rooms.
Penny Emerit, Chief Executive at Portsmouth Hospitals University NHS Trust, said: “This is fantastic news for the local community and staff.
"The planned new facility will enable us to better meet the needs of our local community and improve the experience for patients accessing our ED by providing the best clinical care in a modern, safe environment.
"We have worked with clinical teams to design the layout of the department to not only give us additional capacity but to support them to work in a more streamlined way, with better visibility of our patients and closer access to essential support services such as scans and x-ray.”
The ED will be relocated and sited on the current East Staff Car Park which closed in mid-September to allow site preparation works to begin.
Health Minister Nick Markham said: "The new building will reduce the time patients spend in ED with more treatment rooms and a specially designed entrance to enable a faster turnaround of ambulances, getting them back on the road more quickly.
"As a result patients in Portsmouth and the surrounding area will receive safer and more timely care when they need it, helping to tackle pressures facing emergency services in the South East.”