Northern Ireland's health service is facing a "very difficult winter", the Chief Medical Officer has warned, as cases of Covid-19 are expected to surge over the coming weeks.
Michael McBride said hundreds of coronavirus hospital admissions will lead to a "perfect storm" of additional pressures on the system.
He told the Assembly's Health Committee that frontline medical staff have said it feels like the middle of winter as they prepare to deal with a sharp increase in Covid cases.
"Clearly, any additional admissions over and above the current level of activity will put significant pressures on the health service," Dr McBride said.
"It feels like the middle of winter at this present moment in time.
"If you're in discussion with our frontline staff, you will know that and hear that from them.
"That's on the back of a very long, very difficult past 18 months. Staff are physically tired and exhausted.
"I think that's something that we all must bear in mind."
He also apologised for the "excessive" waiting lists, saying that people are waiting for beds because of ongoing pressures on the hospital system.
Health restrictions, including physical distancing, are still in place in hospitals.
Dr McBride said the combination of restrictions and an increase in the number of people attending hospitals has led to excessive waiting times to access treatment.
"If you then imagine, potentially up to 400 to 600 additional Covid admissions on top of that by late summer into September time, then you can imagine this perfect storm of additional pressures," he added.
"Looking further ahead, I think we will face into very difficult winter."
He warned that it will be "very challenging" for staff who are already "tired and exhausted".
Currently around 80% of the adult population in Northern Ireland has received at least their first dose of a vaccine, with a push on to reach 90% by the end of July.
Dr McBride said that pressure on the health service can be reduced by half if 90% of the population is fully vaccinated.
A number of walk-in vaccination clinics are operating across Northern Ireland in a bid to encourage more people to get the jab.
Health Minister Robin Swann said 180 people received a jab at a pop-up vaccination clinic at Queen's University in Belfast yesterday.
"The people on site engaged just to see why they'd walked in and why they didn't book an appointment and they said 'Well, sure, this is handier'," Mr Swann told the Health Committee.
He said the younger age group is not as engaged as had been hoped, "but if it's on their doorstep, if they can walk past and walk in they are doing that.
"So we are doing more work in regards to that.
"There are a number of TV advertisements now going to run over July and August, supported by UK Government as well, so they're UK-wide."
NI ministers to consider further easing of Covid rules
Northern Ireland Executive ministers will meet today to discuss the possibility of a further easing of Covid-19 restrictions later this month.
It is understood that 26 July will be an indicative date for the next phase of reopening. However, this would have to be ratified by the executive on 22 July.
Among the measures expected to be considered by ministers today are the reopening of theatres and concert halls, a return of conferences and exhibitions, and further relaxations around limits on gatherings in private homes and gardens.
They will also discuss whether to remove the requirement for the wearing of face coverings in places of worship, and subject to public health conditions, the removal of the requirement for masks in classrooms.
It is expected there will be a more cautious approach to reopening in Northern Ireland than the one announced by British Prime Minister Boris Johnson earlier this week.
He said it was his intention to lift the remaining public health measures in England, such as mask wearing and social distancing, from 19 July.
Northern Ireland's Deputy First Minister Michelle O'Neill described his approach as "reckless" and said it would "not be following that model".
Last week, Stormont ministers eased restrictions on live music and outdoor gatherings.
New cases of Covid-19 in Northern Ireland have increased in recent weeks amid growing concern over the spread of the Delta variant, which is the dominant strain of the virus.
Chief Scientific Adviser Professor Ian Young said that cases are "rising rapidly", particularly in the under 40 age group.
There is a big drive to vaccinate as many people as quickly as possible, with a focus on younger people.
Mobile vaccination centres are operating on a pop-up basis at various locations around Northern Ireland to improve accessibility.
These centres and some mass vaccination hubs are offering a "walk-in" service with no appointments needed for those over 18 who have yet to receive their first jab.
The number of people hospitalised with Covid-19 has not grown rapidly, but public health modelling suggests that 400 people could be in hospital with the virus by the end of the summer.
Currently 80% of the adult population has received at least one dose of a vaccine, while 60% are fully vaccinated.
Prof Young said that if the vaccination level rises from 80% to 90%, the modelled hospitalisation figures could be reduced by half.
It is estimated that 85% of people will have one dose by the end of this month.
However, so far just 56% of the 18-29 age group have been vaccinated and health officials want those younger people to come forward.
Elective procedures rescheduled at Altnagelvin Area Hospital
Twenty-seven elective procedures at Altnagelvin Area Hospital in Derry have been rescheduled because of an increase in coronavirus-related admissions in the last 24 to 48 hours and increasing rates of community transmission.
In a statement, the Western Health and Social Care Trust confirmed the move and said: "The situation is being managed in line with our surge planning and is being kept under constant review".
It said it had been in contact with the patients affected and recommends that members of the public "get their vaccine and continue to follow social distancing and public health advice at this time".
