Chief Medical Officer Dr Ronan Glynn says some people are socialising "recklessly" and that it "cannot continue".
200 cases were diagnosed on Saturday and a further 66 on Sunday, though there were no further deaths.
102 cases were recorded in Kildare over the weekend, which remains under lockdown along with Laois and Offaly.
Anthony Staines, Professor in Health Systems at DCU, hopes NPHET tells the government to change course, and quickly.
