A traffic diversion around Northampton General Hospital comes into effect today while developers crane in new pieces of a building.
The Cliftonville entrance to the hospital, off Billing Road, will be closed to all vehicles except ambulances between November 13 December 11.
It comes as contractors begin to assemble a new £12million 60-bed emergency assessment unit next to A&E, set to open in mid-2018.
Meanwhile, a temporary 30-minute drop off point outside A&E will be in place and can be accessed by the Cliftonville Road entrance off Bedford Road.
An NGH spokeswoman said: "Work on NGH’s new 60 bedded assessment unit is progressing well and plans are now being made for the key modules for the building to be craned into place. This work will begin on 13th November and involve some essential diversion of traffic around the site until mid-December to enable the crane and lorry deliveries to operate safely.
"There will be no access to the main reception and A&E area of hospital site from Cliftonville whilst the work is underway, other than for escorted blue light vehicles. In order to gain drop-off access to A&E vehicles will have to follow the diversion route and enter the site from Cliftonville Road."
The hospital is also building a second MRI scanning unit and converting another building into an urgent care treatment centre for patients who would be more appropriately seen by a GP.
The work to take pressure off of A&E comes after the hospital had its busiest ever day last week, with over 400 patients asking for treatment on October 16.