Staff shortages this weekend and next will "have no impact" on Covid testing capacity, Dr Cillian de Gascun has said.
Dr de Gascun, who is head of the National Virus Reference Laboratory, said a number of staff are now self isolating and as a result the lab will close both this weekend and next.
"We agreed this with the HSE to ensure that there would be no impact on the testing capacity over the course of the relevant time frame," he said.
It comes as serious concerns were raised in the Dáil over the fact that National Virus Reference Laboratory will not be able to process swabs this weekend.
Sinn Féin TD Louis O'Reilly told the Dáil that she was "very disturbed" that staffing shortages mean Covid testing will not take place.
Solidarity-PBP TD Richard-Boyd Barrett said the temporary closure of the lab had the potential to "undermine the fight against Covid-19".
But Dr de Gascun said: "We split into two teams to ensure that if one of the teams were affected that we will be able to continue to deliver the service, obviously back in March, April, May it was more significant when we were doing a far greater proportion of the national testing.
"But again, thanks to the work the HSE and the department have put in over the course of the last number of months the majority of testing from the community is now performed at Enfer and obviously all of the hospital laboratories have capacity on site as well," he told RTÉ's New at One programme.
Earlier, Ms O'Reilly asked Health Minister Stephen Donnelly if he was aware of the staffing issue and called him to outline the measures that have been taken to ensure tests are processed.
"I want to ask what efforts have been made to address the short staffing, the fact that they're short staffed in the National Virus Reference Lab I think is very concerning but I want to know what it is that is being done to ensure that that issue is going to be addressed and that the staff are going to be available," she said.
She said we have already seen the "shambles" with tracing but said "testing is absolutely essential".