Arlene Foster last night hit out after deputy First Minister Michelle O'Neill criticised Health Minister Robin Swann for seeking the Army's help to combat the Covid-19 emergency.
Mr Swann revealed he had made a formal request to the Army for help in distributing lifesaving equipment.
He also requested help from the Ministry of Defence (MoD) in planning for a Nightingale hospital at the site of the former Maze Prison.
Mr Swann said: "I believe the Army's skills and logistical expertise could assist with the redistribution of essential lifesaving equipment across Northern Ireland to ensure that all hospitals have the materials and resources required to fully enact their surge plans."
He said he hoped his decision to ask the Army for assistance is not "considered divisive".
But Michelle O'Neill said the Executive should have been informed of his decision before any such request was made. She said she has requested a meeting with Mr Swann over his "failure to consult ministerial colleagues" about his decision.
But DUP leader and First Minister Arlene Foster backed Robin Swann, tweeting: "When your loved one is lying in hospital, who built the ward will be the last thought on their mind.
"Let's build the capacity we need. We fully support the army being used to build necessary beds."
Ms O'Neill said while her party will not rule out any measure necessary to save lives, no proposals to use the Army for roles normally performed by civilians have been put before the Executive.
The Sinn Fein deputy leader added: "I have raised the sensitivities of British military intervention directly with the British Secretary of State Brandon Lewis.
"The Health Minister has a responsibility to exhaust all options, including the use of other blue light public services and civilian contractors, to ensure that ventilators and lifesaving equipment are moved swiftly to where they are needed most.
"The Department for Health has already contracted a local civilian contractor to scope out building a HSC-led civilian 'field hospital'.
"It remains Sinn Fein's position that any proposed new Nightingale hospital should remain under the care and control of the HSC."
Sinn Fein Finance Minister Conor Murphy had previously indicated that the republican party would consider a request for military help if required.