Irish authorities condemned Saturday's protest in Dublin, which resulted in a number of arrests.

Hundreds of protesters, many of them not wearing masks, marched through the city centre, where there was a heavy police presence.

Videos showed one demonstrator point a firework at police before it went off, while other items were thrown at officers.

"Pure thuggery on the streets of Dublin today," Ireland's Minister for Further and Higher Education Simon Harris tweeted.

"It's not a 'protest'. It's an attack on our national effort.

"The abuse directed at the Gardai (police) is sickening and shameful. Disgraceful."

Ireland has been in stage five lockdown since Christmas and about 4300 people have so far died from COVID-19 in the country.

Meanwhile, the Italian regions of Basilicata and Molise were on Saturday elevated to the red zone of Italy's four-tier system of COVID-19 restrictions.

It mean all but essential stores must close and movement is severely restricted in those areas.

Three regions were also moved from yellow to orange zones - Lombardy, Piedmont and Marche - and now bars and restaurants are closed except for take-away.

It comes after a spike in cases in Italy, with more than 20,000 new daily cases and an increase of 35 per cent over the last five days compared to a week prior.

Also on Saturday, a prison in Belgium was placed in lockdown after half of its 132 inmates tested positive for COVID-19, news agency Belga reported.

About half the staff at Namur prison also tested positive.

"The detainees receive a hot meal and hygienic products to clean their cell," a spokesperson for the prison administration was cited as saying.

One prisoner is in hospital, the spokesperson added.

The prisoners had been tested after a positive case was detected earlier this month.

Australian Associated Press