LONDON/BERLIN, March 17 (Reuters) - Some European telecoms operators reported connectivity problems on Tuesday as millions of people logged on for work at home due to the coronavirus pandemic, driving up data traffic by as much as 30% and testing networks.

British carrier O2, owned by Spain's Telefonica, said it had received reports of some customers struggling with its voice network as people hunkered down at home to avoid exposure to the flu-like virus. By mid afternoon, the company said its voice services on its 2G, 3G and 4G networks were returning to normal and apologised to customers.

Governments from Spain to Austria have imposed strict lockdowns to curb the spread of the new coronavirus. Germany, Europe's largest economy, has shut schools and restaurants, causing more people to stay at home.

That is leading to increases in data and voice traffic, but also shifts in how people communicate with each other.

Many people, logged on from home, are using their home Wifi networks to make calls to colleagues, friends and relatives. That increases data consumption via fixed-line networks.

At the same time, more calls are being placed over mobile networks rather than data-driven chat services like WhatsApp, as people check in with elderly relatives who are most at risk from coronavirus but less likely to use messaging apps.

'NEW SITUATION, NO TABOO'

Vodafone's German unit said data traffic was quieter during the day but busier in the evening as people, deprived of the opportunity to go out to a bar or to the movies, spent more time on the sofa binge-watching video streaming services.

"Data use on Monday looked more like it does on a Sunday," said spokesman Alexander Leinhos.

Vodafone Germany, Deutsche Telekom, Telefonica Deutschland all said their networks were working well.

"At the moment we are seeing an increase in data traffic," said Deutsche Telekom, the German market leader. "Until now, all our platforms are coping well."

Isolated reports of connectivity problems may also be because people are trying out data-hungry new videoconferencing apps, overloading the servers on which they run, said one German telecoms industry source.

French telecoms group Iliad said it was not seeing network congestion as a result of lockdown measures in France and Italy.

"Our networks are very busy, of course," said Chief Executive Thomas Reynaud.

He added that the company reserved the right to throttle back the bandwidth allocated to video-streaming services like Netflix, YouTube and Facebook, which dominate networks in the evening.

"We're in a new situation, there's no taboo." (Reporting by Douglas Busvine, Kate Holton, Mathieu Rosemain and Nadine Schimroszik; Editing by Pravin Char)

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