The Chief Executive of the Health Service Executive has said there are no missing flu vaccines after newspaper reports said that hundreds of thousands of doses of the flu vaccine have gone missing.

Paul Reid told the Oireachtas Health Committee the HSE has already distributed almost 1.3 million doses and he said more have been provided up to this week alone than the whole of the flu season last year.

The total distribution is up by around 20% on last year.

Mr Reid said that the final distribution is being delayed so the HSE can see where the allocation is and how to prioritise the remaining vaccines. 

"There is a significant demand out there and we want to ensure that it is prioritised for those groups who are defined as priority," he said. 

Earlier, speaking on RTÉ's Morning Ireland, the HSE's Chief Clinical Officer said 50,000 doses were held back to ensure they are delivered to those areas most in need.

Dr Colm Henry said the HSE normally holds back a certain amount of the vaccine to ascertain where the gaps and priority areas around the country are and where the vaccine needs to be delivered to.

In a letter on Monday, the HSE said the fifth and final cycle of deliveries would be paused until that could be ascertained.

It urged GPs and pharmacists to claim payment for the doses already administered in order to maximise the benefit of the remaining stock.

Dr Henry said the HSE has received records on the administration of over 700,000 vaccines, and it is normal for there to be a lag time between the distribution of the vaccine and records coming back.

He also said it was too early to say it was a mistake not to deliver the children's flu vaccine in schools and that the uptake so far is encouraging.

Speaking later at the committee, Dr Henry said based on the patterns to date, it appears that pharmacists and GPs have confined the flu vaccine to at risk groups.

He was asked how he could guarantee that at-risk groups will receive the remaining 50,000 doses that have yet to be distributed.

Dr Henry said: "Based on our strong consistent messaging and based on our need to prioritise those groups given the stock we have, I am reasonably confident based on the information we have received to date that those vaccines are going to the high priority groups."