The Health Products Regulatory Authority (HPRA) has said it has received 16 reports of blood clots occurring following vaccination with the AstraZeneca Covid-19 vaccine.
It said that none describe a rare blood clot.
The figures are up to the end of March.
The HPRA said that none of the reports describe cerebral venous sinus thrombosis, which is a rare type of blood clot in the brain, nor the occurrence of a blood clot associated with low platelets.
It said that any suspected reports received are being closely monitored and will be considered in the context of the ongoing review with the European Medicines Agency.
It comes as the European Union drug regulator said it is still deciding whether the AstraZeneca coronavirus vaccine causes blood clots, after a top official said there was a clear link.
The European Medicines Agency's safety committee "has not yet reached a conclusion and the review is currently ongoing", the Amsterdam-based EMA said in a statement.
"We will communicate and hold a press briefing as soon as the review is finalised. This is currently expected tomorrow (Wednesday, 7 April) or on Thursday, 8 April," it added.
The statement came after the EMA's head of vaccine strategy Marco Cavaleri was quoted in Italian media as saying that there was a "clear" connection and that the agency would announce it within hours.
"In my opinion, we can say it now, it is clear there is a link with the vaccine. But we still do not know what causes this reaction," Mr Cavaleri told Italy's Il Messaggero newspaper in an interview.
After several countries, including Ireland, paused the use of the vaccine, the EMA said that the benefits outweigh the risks and it should remain in use.
But it has said that a causal link between clots and the vaccine is possible and is expected to provide an updated assessment this week.
"We are trying to get a precise picture of what is happening, to define in detail this syndrome due to the vaccine," Mr Cavaleri said.
We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences
He added: "Among the vaccinated, there are more cases of cerebral thrombosis ... among young people than we would expect."
UK regulators are also examining potential links between the Oxford/AstraZeneca vaccine and rare blood clots.
Reports suggest that the Medicines and Healthcare products Regulatory Agency (MHRA) is considering proposals to restrict the use of the vaccine in younger people.
If confirmed, the roll-out of the UK's vaccination programme could be slowed significantly as more than a fifth of its vaccine supply is tied up in the AstraZeneca jab.
The British government has secured a total of 457 million doses, of which 100 million are from AstraZeneca.
But vaccines minister Nadhim Zahawi said he is "confident" that the commitment to offer a jab to all adults by the end of July will be met.
He said the Moderna vaccine will be rolled out "around the third week of April".
Mr Zahawi said the MHRA looks "very closely" at reports of adverse reactions to the vaccines.
The agency has said it identified 30 cases of rare blood clot events out of 18.1 million doses of the jab administered up to and including 24 March.
There have been seven deaths among the 30 cases.
But the regulator said the benefits of the vaccine in preventing coronavirus outweigh any risks and it urged the public to continue coming forward for the jab.
Channel 4 News reported that the MHRA was considering proposals to restrict the use of the Oxford/AstraZeneca vaccine in younger people and a decision could be made imminently.
MHRA chief executive Dr June Raine said: "People should continue to get their vaccine when invited to do so.
"Our thorough and detailed review is ongoing into reports of very rare and specific types of blood clots with low platelets following the Covid-19 vaccine AstraZeneca.
"No decision has yet been made on any regulatory action."
The 30 cases in the UK include 22 reports of cerebral venous sinus thrombosis (CVST) and eight of other thrombosis events with low platelets.
CVST clots stop blood draining from the brain properly.
But it is not known whether these cases have occurred as a result of the jab, or whether they would have happened naturally in the population anyway.
A number of countries have imposed restrictions on the use of the jab in younger adults.
In Ireland, over 203,000 doses of the AstraZeneca vaccine have been administered to date.
Additional reporting Fergal Bowers, PA