Travel to countries including Malaysia, France and the US has led to people picking up Covid-19 and testing positive for the virus after returning home.
Since June, people who have travelled to Afghanistan, Bangladesh, France, Germany, India, Iraq, Malaysia, Pakistan, Portugal, Qatar, Sudan, Sweden, Ukraine, the United Arab Emirates, the UK and the US have come back with the virus, acting chief medical officer Dr Ronan Glynn revealed.
The extent of the global reach of the virus and its impact here - leading to clusters of infection in some cases - exposed how an infection contracted in a far-flung country can end up being spread here.
It comes amid ongoing concern at the rise in cases reported here in recent weeks.
No new deaths from the virus were reported yesterday, but Dr Glynn said over the past 14 days, the total number of confirmed newly diagnosed cases has reached 165. Of these 59pc are women and the median age is 31.
There were new cases in 20 counties, 47pc of which were in Dublin, 16pc in Kildare and 6pc in Wicklow.
Of these as many as 12pc were travel related, he said.
Public health doctors are continuing to investigate a large cluster of cases arising out of a house party held in Killarney last week.
Some of those infected have since returned to other parts of the country.
"There have been clusters in many counties around the country and our public health teams are on top of those," Dr Glynn said.
He urged people who had been identified as being a close contact of someone who had been confirmed as having Covid-19 to "please go and get tested".
He said the aim was to still stop as much non-essential travel abroad as possible.
Referring to the proposed 'green list' of countries to be published next week - where people can travel without needing to quarantine on their return - he said from a public health viewpoint, there would be less concern about a small list of countries than those areas of the world people are returning from which are not on it.
The advice remains to avoid non-essential foreign travel.
"Our research shows that 38pc of the population now believe the worst of the pandemic is ahead of us," said Dr Glynn.
"This does not have to be the case. Simple measures like hand washing, physical distancing, face coverings in appropriate settings, cough/sneeze etiquette and watching out for symptoms are the crucial elements in suppressing Covid-19."
Department of Health chief nursing officer Rachel Kenna said: "Almost 1.25 million people in Ireland have downloaded the Covid App.
"That represents 34pc of the adult population. This has already served as a support to contact tracers. If you have not done so to date, please download the app."
Dr Siobhan Ni Bhriain, an HSE consultant psychiatrist and integrated care lead, said: "As we see more cases and clusters emerge, it is important that anyone experiencing symptoms isolates and contacts their GP.
"The aim is to find all cases of Covid-19 in Ireland and to isolate and contact trace them.
"Early reporting of symptoms and prompt testing helps us achieve this."
Research shows 55pc of the population now self-report to wearing face coverings.
Some 81pc of people who use public transport say they wear a face covering every time, with 13pc saying they wear a face mask most of the time.