Other countries will use their vaccine supplies to protect their own populations, the Taoiseach said.
Micheal Martin downplayed suggestions Ireland could engage with individual states for unused Covid-19 jabs.
Germany has made it clear it would be using all of its doses.
France is planning to give Astra Zeneca vaccines to people over the age of 65.
Mr Martin said: "Most countries are focused on getting their own vaccinations progressed.
He said a firm stance was being taken at the European Commission level and the important factor was the arrival of the filled vials from manufacturers.
He said: "AstraZeneca are saying that they will make up the shortfalls so far, but we will see as time goes on.
"We are confident of significant additional supplies."
He expressed optimism on meeting inoculation targets over the next number of months.
The Taoiseach added: "Europe is making additional efforts to increase capacity and supply."
All residents and staff in nursing homes and frontline healthcare workers have been vaccinated.
The inoculation of those aged over 85 will be completed within days.
Mr Martin added: "The vaccination programme is having an impact.
Next week, vaccinations will begin of those with underlying health conditions.