The open message said planned appointments and procedures are likely to be affected and could mean further delays for people who are already waiting to see a health care specialist.
The ICB said: “Our services are extremely busy at the moment and we expect them to remain busy and under pressure during the strike.
“NHS health and care providers in Hampshire and the Isle of Wight are working hard to care for our patients while respecting our colleagues’ right to strike.
“We apologize for any disruption you may experience.
“If we have not contacted you to rearrange, please still attend as some services may continue.
“If you are concerned about your health or any changes in your condition since you last spoke to us, contact the team that is caring for you in the same way as you usually would.”
It has issued advice to islanders, including only going to the emergency department or calling 999 if your condition is life-threatening, such as symptoms of a heart attack, stroke, heavy bleeding or difficulty breathing.
NHS managers said, “If your condition is life or limb threatening please do not wait. It is important that patients who need urgent medical care continue to come forward as normal.”
If it is not an emergency, we are told to go to an urgent treatment centre, community pharmacy or GP. Alternatively, 111 online or another phone can help patients who are unsure what to do.
The ICB said: “Our teams have been working incredibly hard and we really appreciate the support we have been receiving from the public and our patients during this challenging time.
“Even as our staff are under extra pressure, please be assured that they are working hard to keep people safe.
“Emergency departments will prioritize patients who need our services for life-saving care, so this will mean longer wait times for less serious conditions.”