16 people have been arrested for anti-social behaviour after large crowds gathered to drink and socialise in the cities last night.
12 people were arrested in Cork and 4 in Dublin.
Gardaí say the Dublin arrests were for public order offences made on South William Street.
They say officers from the Public Order Unit and the Dog Unit dispersed the crowd from the area, along with crowds in Temple Bar and St Stephen's Green.
Significant cleanup operations have been taking place in Dublin and Cork, due to significant amount of waste left behind overnight.
Dublin City Council says staff had to deal with a significant amount of waste left behind overnight - but that it has very few powers to deal with unplanned gatherings of this size.
Chief Medical Officer, Dr Tony Holohan said he was "absolutely shocked" by the enormous crowds in Dublin city centre, and raised concern about its potential impact on our progress against Covid-19.
Tánaiste Leo Varadkar said that he shared the concerns of Dr Tony Holohan about large crowds gathering over the weekend.
The Fine Gael leader is cautious that similar scenes may be seen over next weeks Bank Holiday weekend if the warm weather prevails.
Mr Varadkar told the Irish Times that if a spike in cases occurs, localised lockdowns may be considered:
“Local lockdowns to local restrictions are a policy option, they’re there in the government’s plan. They are a policy option if we have an outbreak in a particular area."
The Portobello area of Dublin and 'Middle Arch' area of Galway City remained closed over the weekend, and these measures may continue for a number of weeks to deter people from drinking in the area.
Gardai are appealing to people not to gather in large groups, maintain social distancing and wear face masks in crowded spaces as the good weather continues.