More families have spoken of the chaos they endured as they tried to get vaccine passports ahead of their summer holidays.
he interim system, which enables people from Northern Ireland to travel to other countries without having to isolate, has struggled to cope with demand since it was launched last week.
On Friday night, the Department of Health issued details regarding the launch of the vaccine app.
It said if you are travelling between July 26 and July 31, you can apply for a certificate through NI Direct or the new app.
It added that the app would be available from the Google Play Store and the Apple App Store but warned it was likely to be popular and there could be delays or capacity problems with accessing the service.
The department advised anyone experiencing problems to wait a while before trying again.
Users are asked to only download and use the app if they are travelling up to the end of July.
Health Minister Robin Swann said: “Covid-19 has created many challenges since it first arrived on our shores last February and our new digital tools have helped us to respond.
“The COVIDCertNI App is the third new smartphone App produced by my department since last year.
“It will enable those travelling internationally to access their vaccination records and show a digital certificate.
“There have been monumental efforts to get this digital platform to this stage.
“I urge the public to remain patient in the coming days as the new process beds in and only apply if you are travelling in the coming days and weeks.
“This has been a complex process with many challenges and I commend everyone involved for getting it to this point.”
Problems that have been encountered this week included a would-be traveller who was told the vaccine passport helpline was due to close for the weekend at 5pm on Friday.
The frustrated caller spent an hour on hold waiting for an update on her application, only to be told that no one could help her because “all the systems are down”.
“They asked me to ring back 20 minutes later. They couldn’t tell me if teams would be working over the weekend to clear the backlog, but they said the helpline would close at 5pm for the weekend,” she added.
A growing number of people have also reported incurring significant additional costs for PCR tests as they face an indefinite wait for a vaccine passport.
Sam Russell, from Dunmurry, said on Friday night: “My wife and I were supposed to be going to Corfu on Thursday past, but we had to make a call on the Wednesday night and change our flight because we hadn’t received our passports.
“We had started the whole application process the Sunday before, so we thought we had plenty of time to get them sorted.
“We were still waiting for the certificates this morning and we’re flying out at the weekend, so I had to start to arrange to get us a PCR test, but there were none available.
“Luckily enough, I was able to get an antigen test at City Airport, so we will be all right, but the whole thing has been a disaster.
“You spend hours trying to get through to the helpline. When you do, you listen to a message telling you how busy they are and then you get cut off.
“I got through once and the person I spoke to didn’t have a clue, wouldn’t take my details and couldn’t phone me back.
All they said was ‘Hopefully you’ll get my certificates’.
“As it is, I lost £40 on our transfer in Corfu, I’ve had to pay £90 for two antigen tests and our holiday is shorter as well.”
Another couple hoping to travel to Majorca this weekend had to pay £200 for a PCR test after one received their vaccine certificate and the other did not.
The 21-year-old health worker said: “My girlfriend and I applied at the same time. Hers has come back and mine hasn’t.
“It’s incredibly frustrating. We haven’t been able to get any answers and it wasn’t worth the gamble not being able to travel, so I’ve had to pay £200 for a PCR test.
“I feel so let down by the whole thing, but it’s typical of here. Anything the government gets involved in turns into a mess.”
Colin Ferguson, another man hoping to travel, said he was passed around a number of departments, including the booking line for the Strangford ferry, as he tried to find out whether his vaccine passport would arrive in time for his holiday.
In a statement issued on Friday afternoon, the Department of Health said the interim vaccine certification system was coming “under extreme pressure”.
The department also asked for patience from the public.