The Irish Travel Agents Association has accused the Chief Medical Officer of creating confusion with remarks that people who are not fully vaccinated should avoid travelling abroad this summer.
It comes as hoteliers have called for Britain to be included on the digital travel system to help the tourism market in Dublin.
The HSE Chief Clinical Officer, meanwhile, has said the best advice for people going abroad is to be vaccinated.
Dr Colm Henry, who is a member of the National Public Health Emergency team, said vaccination is "the safest way to ensure that you won't contract the virus or a variant of the virus abroad and bring it back home".
He was speaking after Chief Medical Officer Dr Tony Holohan yesterday said the public health advice remains for people not to travel abroad for a holiday unless they are fully vaccinated.
The EU Digital Covid Certificate, designed to enable people to travel, is due to come into operation in Ireland from 19 July.
However, Dr Henry said that "the good public health advice is that people shouldn't go abroad unless they are vaccinated".
He said even if people have had a negative test, there is a risk they might contract the disease abroad or a variant and bring it back home.
Buswells is among the hotels in Dublin that usually would be at capacity for the summer months - but this year have average occupancy levels of just 13 to 20%.
Hoteliers say the capital is suffering more from the loss of international visitors than other parts of the country - where staycations are more popular.
They are blaming the impact of self-quarantine restrictions for people travelling into Ireland from Britain:
Buswells General Manager Paul Gallagher said the lack of international travel demand is a "big problem" for Dublin city centre hotels.
Speaking on RTÉ's News at One, Mr Gallagher said he is hopeful that activity from the British market will pick up, but he said he is "unhappy" that vaccinated people "are not allowed to travel freely to Ireland".
He said visitors can expect "great value" for hotel stays in Dublin city centre, with most double rooms starting at €100, and competitive deals for dinner/B&B stays.
Irish Travel Agents Association President Paul Hackett has said demand for booking holidays "is not strong from any cohort".
He said the digital certificate "does not discriminate" against people who are unvaccinated.
"We need to get the message out there, very simply, and straightforwardly on who can travel. The Digital Covid Certification is not a vaccination certificate. It was designed in such a way that we were not to discriminate against people who were not vaccinated, we were to offer them the alternative of negative test results for recovery from Covid."
Meanwhile, the Oireachtas Committee on Transport and Communications has "strongly recommended" the immediate roll-out of a rapid antigen testing pilot programme for aviation.
Following the committee's meeting with NPHET representatives on Wednesday, it wrote to Minister for Transport Eamon Ryan urging the commencement of such a programme.
Chairperson Kieran O'Donnell said it appeared as if the Government-commissioned Report of the Covid-19 Rapid Testing Group has yet to be fully discussed and considered by NPHET.
The committee is now calling for an "immediate" review of the publication, commonly referred to as the Ferguson Report.
"Our committee has strongly recommended to the Minister for Transport Eamon Ryan that the Government without delay write to and engage directly with Dr Holohan, NPHET and the aviation sector to immediately roll-out a rapid antigen pilot testing programme," Mr O'Donnell said.
The Fine Gael TD added: "It is vital that the logistics and ICT systems for mass serial rapid antigen testing are in place and in line with the introduction of the EU Digital Covid Certificate here."
The committee recommended that the Government's chief scientific advisor and member of NPHET, Professor Mark Ferguson, and his colleagues on the Covid-19 Rapid Testing Group are consulted.
"In their report published nearly three months ago, the Covid-19 Rapid Testing Group recommended that pilot programmes of serial rapid antigen testing commence at scale and at pace across various sectors, including the aviation sector," he said.
Mr O'Donnell said clarity on why there has been such a delay in a pilot programme for aviation being rolled-out is needed.
"The Joint Committee on Transport and Communications remains of the view that all available Covid-19 testing options must be fully explored as part of the Covid-19 public health toolkit, including rapid antigen testing," he added.