Updated 6.40pm

EU health ministers met on Tuesday as national governments step up measures to try to curb the Omicron Covid-19 variant spreading across Europe while winter closes in.

The gathering aimed for greater coordination of bloc-wide measures in response, such as travel recommendations, and to hear pleas from the European Commission to accelerate vaccinations.

All participants "acknowledged that we're facing a very challenging epidemiological situation," EU health commissioner Stella Kyriakides told a media conference.

Developments seen with the spread of the Omicron variant over the past two weeks show "we must take urgent action -- urgent and coordinated action," she said.

Priority should be given to vaccinations, to close the "immunisation gap", she said, noting that six EU countries still had vaccination rates of below 55 per cent of their populations.

"Safe and effective therapeutics" for those already infected also needed to be approved and made available, Kyriakides said.

Health Minister Chris Fearne emphasised the importance of rapidly rolling out booster vaccine doses. 

"Malta's decision to start administering booster shots early appears to have been a wise one, and now other EU countries are following suit," he said following the meeting. 

Healthcare workers are currently administering booster doses to all residents aged over 50. Malta's vaccination programme will also expand to include children aged five to 11 in the coming days, once doses intended for children have reached the island. 

Earlier, Polish Health Minister Adam Niedzielski stressed that near-term "forecasts are not optimistic" for Europe as the continent goes into its of end-of-year period of traditional family get-togethers. 

Member states retain the final say on their individual health-related decisions, raising the prospect of a patchwork of restrictions across the 27-nation European Union as Christmas and ski trips loom.

The Omicron issue is the first order of business for an EU summit on December 16, according to a draft agenda seen by AFP.

"We have all seen in the last weeks the true scale of the challenge we still face against the virus that the world cannot yet shake off," European Commission chief Ursula von der Leyen told EU ambassadors on Tuesday in a video address.

274 Omicron cases and counting

While questions about Omicron's severity and ability to escape immunity cannot be answered for a couple more weeks, initial data confirm its high transmissibility.

Britain, for instance, on Tuesday reported it now has 437 cases -- the biggest number recorded by any European country.

First detected in southern Africa two weeks ago, Omicron cases have been registered in dozens of countries. 

Initially, they were tracked to travellers from Africa, but now there are clusters of infections in several countries suggesting community spread. 

The European Centre for Disease Prevention and Control (ECDC) on Tuesday counted a total 274 Omicron cases across the EU and in its associated European Economic Area (EEA) neighbours Iceland, Liechtenstein and Norway. 

The biggest number of cases in the EEA were in Denmark with 73, Portugal with 34, France on 25, the Netherlands with 24, and 19 in Norway. 

Some of those countries -- Denmark and Norway in particular -- announced even higher parallel tallies based on different Covid variant detection techniques.

Given Omicron's exponential rise, the ECDC has said it expects the variant to become dominant in Europe within months.

While the EU is putting greater emphasis on vaccinations, there is an understanding that inoculation alone was not enough. 

Underscoring that, Denmark's double-jabbed Health Minister Magnus Heunicke tested positive for Covid just before he was to attend the meeting. He went into quarantine in his hotel room instead. 

As well as reinforcing the use of masks, social distancing and adequate ventilation, the EU is advancing with Covid-19 treatments.

On Tuesday, the European Commission approved another of those synthetic treatments for critical patients, sold as Actemra or RoActemra by Roche, according to the Swiss-based company.