An associate professor in biochemistry says reducing down essential workers could be one way to help get coronavirus numbers under control.
It comes after Taoiseach Micheál Martin said level five restrictions will continue into February.
He told his parliamentary party on Wednesday night that the numbers remain too high.
Tomás Ryan is associate professor in the School of Biochemistry and Immunology at Trinity College Dublin (TCD).
He told Newstalk Breakfast too many people are still moving around.
"There's still a lot of people going to work, and so we could reduce that by reducing what essential workers are.
"We could reduce the radius around us - we could go from the 5km limit to a 2km limit - we could ask the Government to engage in things like mass antigen testing, which still hasn't happened in serial testing of healthcare workers.
"And I think it's also fair to say that we don't really know how many infections are coming through hospitals and into the communities".
But he said a timeframe is not the big issue here.
"The crucial thing is not about how long we need to be in restrictions, I think when we ask that question we're setting ourselves up for the same problems as before.
"The question needs to be when can we get control of the virus - when we get control of the virus, then we can start to open up".
He suggested this would need to see a level of "about 10 cases a day."
"When you get to that level of virus case number, that's in the zone where our test, trace and isolation infrastructure can manage it".
Prof Ryan said the reason for the high case numbers could be largely down to the "newbie 117 variant - what we call the British variant - which is significantly more transmissible."
"And now probably makes up most of the virus population in Ireland, though we don't have perfect surveillance on that yet".
"Our behaviours could also be stricter - based on traffic and based on mobility analysis, we're not exactly restricting our movements as much as we did in the first lockdown".
A further 61 deaths and 2,488 new case were reported here on Wednesday - while there were 1,923 people in hospital with the virus and 210 in ICUs.
The National Public Health Emergency Team (NPHET) will meet later to consider the current situation.
While the Cabinet Sub-Committee COVID-19 will gather next Monday and get an update from NPHET, the HSE and public health experts.
A recommendation will then go to the full Cabinet next Tuesday.