A memorandum of understanding has been signed by the departments of health in Northern Ireland and the Republic of Ireland to strengthen co-operation in the battle against coronavirus.
The document focuses on facilitating greater co-operation on areas such as public health messaging, research, programmes of behavioural change and pharmaceutical measures.
It has been agreed by the two health ministers, Simon Harris and Robin Swann, and the two chief medical officers Dr Tony Holohan and Dr Michael McBride.
The document has the support of the Stormont Executive and the Irish Government.
Mr Swann said: “I want to acknowledge the ongoing collaborative work between my Department, the Public Health Agency and Health and Social Care Board and their counterparts in the Republic of Ireland. This has been the case from day one and is a reflection of the long standing cooperation and relationships built up over many years.
"We face a common challenge, a challenge that will test us as never before. We will continue to do everything possible to work together for the best possible outcome.”
Dr McBride, who is chief medical officer for Northern Ireland, said the document "reaffirms" the commitment between the two countries to work together during the health crisis.
He added: "North-south co-operation on protecting the health and well-being of our citizens has been well established for many years. It is essential that we continue to work together as closely as possible at this time.”
Mr Harris said: "There has been significant engagement between the ministers, the chief medical officers, and the departments throughout this pandemic.
"This MOU will ensure timely and responsive communications and decisions in a fast-moving environment; that both administrations will seek to adopt similar approaches, where it is appropriate to do so on the advice of respective chief medical officers.
"I want to thank my colleagues in Northern Ireland for their co-operation to date. This is a global pandemic. It knows no borders and we are all in this together. It is essential we continue to do everything we can across the island to fight this pandemic."
Dr Holohan, chief medical officer for the Republic of Ireland said: "We have been working closely with our Northern Irish colleagues since the start of the COVID-19 crisis. Today's MOU will formalise the close ongoing co-operation that has been taking place."