Newly published letters have revealed tensions between the HSE and the National Public Health Emergency Team (NPHET).
Despite the government repeatedly denying any rift in the coronavirus decision-making process, newly-published letters paint a different picture.
In one of the letters HSE boss Paul Reid expresses anger that NPHET announced an expansion of coronavirus testing to 100,000 a week, without informing the HSE which carries out the tests.
In mid-April, the Chief Medical Officer and Chair of the National Public Health Emergency Team Dr Tony Holohan announced a target of 100,000 tests being carried out a week.
It's now emerged that was done without the HSE signing off.
HSE boss Paul Reid subsequently wrote to the head of the Department of Health, expressing concerns at the decision making process.
The HSE carries out the testing, and Mr Reid said he was "extremely disappointed" that understandings around decision making were not respected.
He raised further concerns about the ability of the HSE to meet those targets.
In the Dáil this afternoon, Labour leader Alan Kelly called the letters explosive.
Health Minister Simon Harris tried to play them down, saying a number of HSE staff are on the NPHET team that made the decision.
He suggested that there's always robust debates around decisions at this level.