The Courts Service has said it has sought urgent advice in relation to court sittings going on for two hours or more.
It said that until it receives such advice, all court sittings will last no longer than two hours in each day.
This follows yesterday's advice to TDs that they should not spend more than two hours a day inside the Dáil chamber with each other.
In a statement, the Chief Justice and the Presidents of the Courts referred to the advice given to the Houses of the Oireachtas.
The Courts Service said it was unaware, until the matter became public yesterday, of this advice, which it described as "additional safety considerations beyond those already published".
The service said the plans that had been devised by the judiciary and the Courts Service to expand the number of physical hearings had taken full account of all published advice.
It said that they had sought further urgent advice as it clearly had the potential to affect the conduct of court hearings, likely to involve judges and registrars, and others being in a courtroom for more than two hours a day.
In the meantime, the presidents had determined that all court sittings would last for no more than two hours in each day. It said the decision did not apply to remote hearings.
Chief Medical Officer Dr Tony Holohan has said that the guidance was that no two people should spend a cumulative period of more than two hours in the same room in any 24-hour period.
But he said it was not to be interpreted as a hard and fast rule to all sectors. He said a risk assessment would take into account a number of factors, including the degree of ventilation, the size of the room and the nature of the work.
In a statement, the Department of Health said it was unable to comment on the specific advice given to the Oireachtas, which was provided by the Health Protection Surveillance Centre of the HSE.
"However, HPSC Guidelines in the identification of contacts for contact tracing purposes states that for those contacts who have shared a closed space with a case for longer than two hours, a risk assessment should be undertaken taking into consideration the size of the room, ventilation and the distance from the case. This may include office and school settings and any sort of large conveyance."
If an individual within that group were to become Covid positive, the statement said, then everyone else within that confined space may be considered to be close contacts of each other, with the default public health advice to self-isolate for two weeks.
"Public health officials will, in the course of the contact tracing process, assess the physical shape of the room, presence of windows, surfaces, etc, to determine the extent to which everyone in the room are actual close contacts."
The Department said employers are therefore being encouraged to risk assess all work practices in their organisations to minimise the potential of employees becoming close contacts of each other.
Employers are also being asked to consider the implications of their workers being designated as close contacts, leading to two weeks of self-isolation, and to build in contingencies into their workforce planning accordingly.
The Director General of the Law Society, the body representing solicitors, said the direction confining hearings in courtrooms to just two hours per day was very surprising indeed.
Ken Murphy said it was bordering on bizarre that Ireland was being given this advice for the first time, more than two months into the crisis.
He said the Dáil had frequently sat for well in excess of two hours during this time and businesses and workplaces of all kinds had been kept in ignorance of this advice, by the Department of Health.
He added that if this dramatic new advice was to be followed, it represented a disappointing setback to the valiant efforts being made by the Courts Service to reopen the courts in the public interest.
Barrister Tony McGillicuddy estimated that just ten per cent of court business may be able to continue under two-hour restrictions.
Speaking to RTE's Drivetime, Mr. McGillicuddy also indicated it would be "very very difficult for jury trials to proceed" should the two hour limit be in place.
Health officials have moved to clarify the advice to TDs that they should not spend more than two hours a day inside the Dáil chamber with each other; intimating there's no steadfast blanket rule for all workplaces. They've also pointed to how a two-three day turnaround time for testing and tracing may supersede the need for 14 days self isolation.
However, Mr. McGillicuddy feels this too could have major ramifications for jury trials going forward.
"Trials are a live process. There's a momentum to them, where there's a witness in the witness box who would be giving evidence today and has to come back tomorrow. If you lose two days in between; there would be inherent difficulties and it adds to the stress and difficulty of the overall situation," he said.
Mr McGillicuddy said the Government may need to provide funds to the Courts Service to fund innovative ways to ensure litigation can go ahead.
Others have pointed out that retail workers, factory workers and healthcare workers have been working shifts lasting much longer than two hours since this crisis began.
Meanwhile, summonses against 17 people listed for Tullamore District Court this afternoon were adjourned because of the new restrictions.
Judge Bernadette Owens announced this morning that she had just received a direction from the President of the District Court that courts in any one venue should not go on for any more than two hours.
"It certainly curtails very significantly the time that we have today," she told the court.
With the exception of one prosecution which was struck out, all summonses were adjourned to 2 September.