The HSE chief executive says an increasing number of people are not answering calls from Covid-19 contact-tracers.
Paul Reid says it's a 'concerning trend' because they are a valuable resource to protect people against the virus.
Contact-tracers identify people who were in close contact with someone who has Covid.
765 cases of the virus were confirmed yesterday, but fewer tests were carried in the days around Christmas.
The Irish College Of General Practitioners' Covid Lead, Dr Nuala O'Connor, says GP out of hours services have been very busy.