The World Health Organisation's COVID-19 Special Envoy is “not so keen” on vaccine status being used to allow people access to venues.
Dr David Nabarro was speaking as Cabinet meets today, with ministers set to delay the reopening of indoor dining in pubs and restaurants for at least two weeks.
However, NPHET has suggested a system should be developed so indoor hospitality - apart from hotels - would be limited to people who are fully vaccinated.
Speaking to Newstalk, Dr Nabarro said the WHO's "nervous" about such an approach as it could lead to inequality.
He said: “Whilst I understand people calling for the use of vaccine status to be something that determines whether or not people can get into a venue or country… I myself, in the current circumstances, am not so keen on that.
“Access to vaccines is so unequal in our world, and I don't want anything to happen that increases the inequalities.
“If you use vaccine status as a requirement for entry to something, you’re also blocking out an awful lot of people from having any chance of participating.”
The Government wasn’t expecting such a recommendation from NPHET, and some ministers have admitted it will be a logistical nightmare for many businesses to track.
Green Party leader Eamon Ryan this morning said it’s something they now “need to consider and look at how we manage it”, noting he himself his previously spoken publicly about the difficulties of implementing such a system.
Ministers are considering the proposal again this morning, and the Government is then expected to hold talks with hospitality industry groups about the idea.
The Restaurants Association of Ireland has already dismissed the proposal as “flawed, unworkable, discriminatory and currently illegal"
