Around 100 medically trained personnel are expected to be deployed.
Members of the military are to be brought in to help medical staff cope with the pandemic in Northern Ireland.
More than 100 medically trained technicians will provide nursing support to an NHS battling to avoid being overwhelmed by the deluge of Covid-19 cases.
It is envisaged they will work in badly stretched hospital wards.
Health Minister Robin Swann said: “Our hospitals are under immense pressure and an additional staffing complement will be very welcome on the frontline.
“This is a health decision and I am confident it will be supported on that basis.”
Use of the Army has prompted tensions in the past in Northern Ireland but it has previously helped out with weather-related incidents.
The health system is facing the peak of a wave of coronavirus-related admissions this week into next.
The minister added: “I welcome this agreement, which comes at a particularly challenging and critical period for our health service.
“The Armed Forces have provided invaluable support in this pandemic, including aeromedical evacuation, real-estate and ongoing logistical planning.
“I thank the MoD for this support and for this timely Military Aid to the Civil Authorities (MACA) agreement finalised today.”
In April, Mr Swann said he had requested the aid but Sinn Fein’s deputy First Minister Michelle O’Neill said he had taken that decision unilaterally.
There have been a further 22 deaths of patients who tested positive for coronavirus in Northern Ireland.
Another 905 people have tested positive, according to the latest department of health figures.
On Wednesday, there were 832 Covid-positive patients in hospital, 67 of whom were in intensive care units.
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