The First Minister says that people living in Wales will be able "within the next few days" to prove their vaccination status via the NHS system available to people living in England.
But Mark Drakeford said it would be using a web portal rather than the app that is available to users in England and it won't be accessible in the Welsh language.
In England, as many as six million people use the NHS app as a form of vaccination passport when booking events or international travel.
This is a different app to the NHS Covid app which is part of the track and trace system and is fully available to people living in Wales.
During First Minister's Questions, Mark Drakeford was asked about access to the system by a fellow Labour Senedd Member, Hefin David.
He said a constituent had contacted him to say that the process of applying for a vaccination certificate was "archaic and slow" compared to the process in England.
He pointed out that the Welsh government had previously said people in Wales would be able to use the same process "roughly four weeks" after its introduction in England, which was on May 17th.
The First Minister said he disagreed that the current system was "archaic" and that over 10,000 people have received certificates through that method.
He blamed the delay on "technical reasons largely connected to the reconfiguration of the English solution to meet Welsh requirements" but that it would be available "once the English system manages to do its job and to make access for Welsh people available to it." And he added that that would be "within the next few days."
However he told MSs that it would only be available in English for the first few months.
"I'm afraid Llywydd, it will not be available in Welsh. Despite repeated requests to the UK Government to respect the law here in Wales, they tell us they won't to be able to do that for several more months."It also won't be accessible via a similar NHS app but via a web portal.
Mr Drakeford added: "The journey thereafter will be identical to the app and Welsh people will be able to use it in real time in the way that the English system has been available in England since the 17th of May."