There's been no advice on changing the interval period for the Pfizer and Moderna Covid-19 vaccines, according to the Acting Chief Medical Officer.
The Government is believed to be considering extending the gap between the first and second doses from four weeks to between six and eight.
Some experts claim it would give the country the ability to give 80 percent of adults a first dose by the end of May.
Dr Ronan Glynn says officials are waiting to see what happens with the Johnson and Johnson vaccine:
Meanwhile, the HSE will give an update on when people can get a Covid-19 vaccine over the coming months when it goes before the Oireachtas Health Committee later.
It's believed people aged 59 are due to receive a first dose of a vaccine in early May.
The plan is expected to exclude Johnson and Johnson's vaccine - the roll-out of which has been put on hold due to concerns of blood clotting events in the US.
The National Immunisation Advisory Committee will also attend the hearing.
Health Committee Chair is Fianna Fáil's Sean Crowe - he said despite progress there are still a lot of concerns surrounding the roll-out: