The comments from Gerry Killeen came as it emerged that the National Public Health Emergency Team (Nphet) is to meet today to consider its advice to Government on whether or not to further ease Covid-19 restrictions from July 5.
A decision on the return to indoor hospitality had initially been expected later this week, but ministers have faced intensifying calls from bar and restaurant owners to urgently provide clarity.
Mr Killeen, who is the AXA research chair of applied pathogen ecology at University College Cork, said he felt the country has a maximum of a week or two weeks to act on the Delta variant before the country is headed for another lockdown.
The infectious diseases expert said he also believes local lockdowns should be used to break the chain of infection, and said Cork would be on the list of areas he would like to see locked down.
Mr O’Donovan said there were a lot of pubs in rural areas depending on the staycation market for the next 10 weeks and any delay would be a serious blow.