The level of Covid-19 community transmission in Ireland has doubled in the last 10 days, an expert has revealed.
Professor Professor Philip Nolan of the National Public Health Emergency Team said that the level of community transmission was "difficult to monitor" and that it was very low just weeks ago.
He explained that this recent spike was the primary factor in Taoiseach Micheal Martin announcing a range of new measures to combat the virus on Tuesday.
The turn-around time for testing and contact tracing has also risen dramatically to 2.85 days in recent weeks, up from 1.93 days on July 16.
Mr Nolan, who is the Chair of NPHET's Epidemiological Modelling Advisory Group, said: "One of the things that is difficult to monitor is the level of community transition, and the reason is this is that every case requires detailed investigation by public health teams, and it's only after that investigation that you know where someone has picked-up the disease.
"So we've had several hundred cases reported in the last seven days, prior to that, the level of community transmission was very low.
"But of those hundreds of cases reported in the last seven days, some we know to be associated with outbreaks but a significant proportion remain under investigation and it's not yet clear whether they are community transmission or linked to a contact or linked outbreak, but we do know the level of community transmission appears to have doubled in the last 10 days, so that's the reason we're moving at this point."
Professor Nolan said it was urgent that we moved to try and limit the spread of the virus between households, before it gets out of hand and becomes 'unsustainable'.
He told RTE's Morning Ireland: "I think the Taoiseach is correct, what we've seen over the last several weeks is a slow but very particular rise in the level of the disease in the population.
"We've seen the virus spread essentially from workplaces to households and now from households into the community.
"The rate of growth is significantly slower than it was at our other critical juncture back in late February and early March, but it is too fast.
"Unless we move quickly now together to prevent further transmissions between households, and from households and into the community, and that's the core message behind these interventions, to limit our social contacts, and to limit those social contacts to small groups, unless we move no collectively and firmly to prevent further transmission of the virus, we will see case numbers rising to a level that our unsustainable."
Professor Nolan was pressed on whether he was 'concerned' that the Government did not listen to all of NPHET's advice, which included reducing opening hours for restaurants and limiting the number who can attend weddings to 15.
"This is the way we work," he said.
"NPHET makes its recommendations from a public health perspective and Government decides.
"There were recommendations made that Government wants to engage in greater detail on or think through further, or is not prepared to accept. That happens.
"But I think the core message remains the same, what both NPHET and the Government are saying to people is 'we are at this critical juncture.'
"The central recommendation, and that central recommendation to avoid congregation, to limit parties to six people indoors, and by parties I mean groups of people."
Professor Nolan added that the number of people limited to attend indoor and outdoor gatherings is based on 'risk-analysis'.
