Preparations to build the new deck above Car Park B at KGH start this weekend and will see the car park shut tomorrow (Saturday).
The work involves big machinery coming to site and carrying out pressure/load testing on the ground in and around the car park.
As a result it will need to be closed to all traffic from midnight tonight and all day Saturday.
Car Park C (next to the diabetes centre) will be made available to members of the public to use as an alternative.
A spokesman for Kettering General Hospital said: “The changes should bring some significant improvements to car parking and traffic flow on the KGH site.
“The decking will mean significant extra spaces for patients and should reduce queueing.
“The changes to car park A should make it easier for disabled people and all those involved in short-stay drop-off at the hospital – and again this should help to reduce queuing on site.
“At busy times we were very aware that queuing and potential breakdowns of vehicles could potentially block the ambulance run down to A&E, putting patients at risk.
“By introducing the red route – along with level crossing type flashing lights to halt vehicles accessing car park A when ambulances are coming on to site – we can ensure that patients with life-threatening conditions reach A&E as quickly as possible.”
KGH added that they understand that some patients and visitors of the trust have experienced difficulty when visiting.
They offered their deepest apologies and say they have listened to concerns and are currently looking to address the problems.
Once complete, the second deck will provide an extra 224 spaces in Car Park B.
The work is part of the hospital’s wider plans to improve traffic flow and parking provision.