More than 10,000 people have now joined the local fight against coronavirus.
An appeal to bolster the health and social care workforce prompted a huge response in just 72 hours.
The figures, revealed by the UUP Health Minister Robin Swann on Tuesday, showed an additional 2,000 had registered since Monday.
The scheme was announced by the Department of Health at the weekend, with Mr Swann telling the public: "Northern Ireland needs you."
At least 1,500 of the total registrations were made by clinical staff. The number of people signing up doubled from around 4,000 to over 8,000 within 48 hours of the scheme opening.
The Department of Health plans to invite second-year nursing, midwifery and allied health professions, including physiotherapy, radiography and occupational therapy, to further support care delivery as part of the scheme.
Non-clinical workers are also needed for paid employment, including as porters, catering staff, cleaning and domestic services staff.
Mr Swann hailed the response as great news for Northern Ireland and thanked the public for stepping up to assist our health workers.
One of the retired clinicians returning to help is Progressive Unionist Party councillor and retired GP Dr John Kyle (68).
He told the Belfast Telegraph he felt "motivated" to sign up to the workforce, having stepped down from his east Belfast practice last year after 35 years in the profession.
"I felt that I wanted to do my part," explained Dr Kyle.
This is the right thing to do, and taking that approach, it's less fearfulDr John Kyle
The councillor said that he had yet to find out what role he had been assigned, but he was aware that he was one of many clinical staff returning to the health service.
He revealed that he had spoken with his wife Helen and his five grown-up children before making his mind up because he did not want to expose them to the virus.
Frontline health workers have contracted the virus and one consultant in England has died because of it.
Dr Kyle said: "My family are supportive. Some were concerned for me. For me, it's probably not wise to dwell on it too much. That's how I personally deal with things.
"This is the right thing to do, and taking that approach, it's less fearful."
Dr Kyle, a former interim leader of the PUP, said he had been heartened by the support his party had shown to his decision to register for the scheme.
"I've also had messages of support from friends as well as the wider community," he added.
"I've been inundated with kind words and I'm very grateful for that."
Across the UK, more than 700,000 have signed up to an NHS campaign which will support the 1.5 million vulnerable people told to shield themselves from Covid-19.
The Department for Communities is also co-ordinating a large-scale community volunteering operation, providing support to older and vulnerable citizens.
This campaign is linking in with neighbourhood initiatives and work by the community and voluntary sector, faith groups and others.
Communities Minister Deirdre Hargey revealed on Tuesday more than 1,000 people had signed up in less than a week.
She said: "A partnership response between government and the voluntary and community sector has never been more important as we face a public health emergency in which there is a need to protect and support those vulnerable people across our communities.
"I have established a voluntary and community sector emergencies leadership group which brings together experts in emergency planning and our most experienced grass roots leaders."
This is what joined-up Government looks like - different departments working alongside each other and with the public to make a real difference in vital areasRobin Swann
Last week Volunteer Now launched a new online campaign called #HelpEachOther to support those who wish to volunteer for Covid-19 opportunities.
It will also assist organisations which require the support of volunteers to deliver their services to those who need it most.
Mr Swann praised both schemes, saying: "It is impressive and encouraging that so many people are stepping forward, both for the HSC recruitment drive and the separate community volunteering opportunities.
"This is what joined-up Government looks like - different departments working alongside each other and with the public to make a real difference in vital areas.
"If you cannot join the ranks of the workforce or do volunteering work in your community, you can still make a huge contribution by sticking to the public health guidelines.
"As a prominent doctor said this week, we can all be heroes."